# wla-dx 10.7 documentation

- 1. Introduction
- 2. Quickstart
- 3. Assembler Directives
  - 3.1. `.16BIT`
  - 3.2. `.24BIT`
  - 3.3. `.ADL ON`
  - 3.4. `.8BIT`
  - 3.5. `.ACCU 8`
  - 3.6. `.ADDR 16000, main, 255`
  - 3.7. `.ALIGN 4`
  - 3.8. `.ARRAYDB NAME MyArray INDICES '0', 0, 1`
  - 3.9. `.ARRAYDD NAME MyArray INDICES '0', 0, 1`
  - 3.10. `.ARRAYDEF NAME MyArray SIZE 256`
  - 3.11. `.ARRAYDEFINE NAME MyArray SIZE 256`
  - 3.12. `.ARRAYDL NAME MyArray INDICES '0', 0, 1`
  - 3.13. `.ARRAYDW NAME MyArray INDICES '0', 0, 1`
  - 3.14. `.ARRAYIN NAME MyArray INDEX 0 VALUE 10`
  - 3.15. `.ARRAYOUT NAME MyArray INDEX 0 DEFINITION ArrayOut`
  - 3.16. `.ASC "HELLO WORLD!"`
  - 3.17. `.ASCIITABLE`
  - 3.18. `.ASCSTR "HELLO WORLD!", $A`
  - 3.19. `.ASCTABLE`
  - 3.20. `.ASM`
  - 3.21. `.ASSERT VALUE_1 == 1`
  - 3.22. `.BACKGROUND "parallax.gb"`
  - 3.23. `.BANK 0 SLOT 1`
  - 3.24. `.BASE $80`
  - 3.25. `.BITS 4 DATA %1011, %0100, %1010, %0101`
  - 3.26. `.BLOCK "Block1"`
  - 3.27. `.BR`
  - 3.28. `.BREAK`
  - 3.29. `.BREAKPOINT`
  - 3.30. `.BYT 100, $30, %1000, "HELLO WORLD!"`
  - 3.31. `.CARTRIDGETYPE 1`
  - 3.32. `.COMPUTEGBCHECKSUM`
  - 3.33. `.COMPUTEGBCOMPLEMENTCHECK`
  - 3.34. `.COMPUTESMDCHECKSUM`
  - 3.35. `.COMPUTESMSCHECKSUM`
  - 3.36. `.COMPUTESNESCHECKSUM`
  - 3.37. `.CONTINUE`
  - 3.38. `.COUNTRYCODE 1`
  - 3.39. `.DATA $ff00, 2`
  - 3.40. `.DB 100, $30, %1000, "HELLO WORLD!"`
  - 3.41. `.DBCOS 0.2, 10, 3.2, 120, 1.3`
  - 3.42. `.DBM filtermacro 1, 2, "encrypt me"`
  - 3.43. `.DBRND 20, 0, 10`
  - 3.44. `.DBSIN 0.2, 10, 3.2, 120, 1.3`
  - 3.45. `.DD $1ffffff, $2000000`
  - 3.46. `.DDM filtermacro 1, 2, 3`
  - 3.47. `.DEF IF $FF0F`
  - 3.48. `.DEFINE IF $FF0F`
  - 3.49. `.DELFUNCTION SUM_AB`
  - 3.50. `.DELMACRO TEST`
  - 3.51. `.DESTINATIONCODE 1`
  - 3.52. `.DL $102030, $405060`
  - 3.53. `.DLM filtermacro 1, 2, 3`
  - 3.54. `.DS 256, $10`
  - 3.55. `.DSB 256, $10`
  - 3.56. `.DSD 256, $1ffffff`
  - 3.57. `.DSL 16, $102030`
  - 3.58. `.DSTRUCT waterdrop INSTANCEOF water VALUES`
  - 3.59. `.DSW 128, 20`
  - 3.60. `.DW 16000, 10, 255`
  - 3.61. `.DWCOS 0.2, 10, 3.2, 1024, 1.3`
  - 3.62. `.DWM filtermacro 1, 2, 3`
  - 3.63. `.DWRND 20, 0, 10`
  - 3.64. `.DWSIN 0.2, 10, 3.2, 1024, 1.3`
  - 3.65. `.ELIF defined(DEBUG) && VERSION > 110`
  - 3.66. `.ELSE`
  - 3.67. `.EMPTYFILL $C9`
  - 3.68. `.ENDASM`
  - 3.69. `.ENDA`
  - 3.70. `.ENDB`
  - 3.71. `.ENDBITS`
  - 3.72. `.ENDEMUVECTOR`
  - 3.73. `.ENDE`
  - 3.74. `.ENDIF`
  - 3.75. `.ENDME`
  - 3.76. `.ENDM`
  - 3.77. `.ENDNATIVEVECTOR`
  - 3.78. `.ENDNG`
  - 3.79. `.ENDNGSOFTDIP`
  - 3.80. `.ENDNGVECTORS`
  - 3.81. `.ENDRO`
  - 3.82. `.ENDR`
  - 3.83. `.ENDSNES`
  - 3.84. `.ENDST`
  - 3.85. `.ENDS`
  - 3.86. `.ENDU`
  - 3.87. `.ENUM $C000`
  - 3.88. `.ENUMID ID_1 0`
  - 3.89. `.EQU IF $FF0F`
  - 3.90. `.EXHIROM`
  - 3.91. `.EXPORT work_x`
  - 3.92. `.FAIL "THE EYE OF MORDOR HAS SEEN US!"`
  - 3.93. `.FARADDR main, irq_1`
  - 3.94. `.FASTROM`
  - 3.95. `.FCLOSE FP_DATABIN`
  - 3.96. `.FILTER filtermacro 1, 2, "encrypt me"`
  - 3.97. `.FOPEN "data.bin" FP_DATABIN`
  - 3.98. `.FREAD FP_DATABIN DATA`
  - 3.99. `.FSEEK FP_DATABIN 10 START`
  - 3.100. `.FSIZE FP_DATABIN SIZE`
  - 3.101. `.FTELL FP_DATABIN POSITION`
  - 3.102. `.FUNCTION SUM_AB(varA,varB)`
  - 3.103. `.GBHEADER`
  - 3.104. `.HEX "a0A0ffDE"`
  - 3.105. `.HIROM`
  - 3.106. `.INESHEADER`
  - 3.107. `.IF DEBUG == 2`
  - 3.108. `.IFDEF IF`
  - 3.109. `.IFDEFM \2`
  - 3.110. `.IFEQ DEBUG 2`
  - 3.111. `.IFEXISTS "main.s"`
  - 3.112. `.IFGR DEBUG 2`
  - 3.113. `.IFGREQ DEBUG 2`
  - 3.114. `.IFLE DEBUG 2`
  - 3.115. `.IFLEEQ DEBUG 2`
  - 3.116. `.IFNDEF IF`
  - 3.117. `.IFNDEFM \2`
  - 3.118. `.IFNEQ DEBUG 2`
  - 3.119. `.INC "cgb_hardware.i"`
  - 3.120. `.INCBIN "sorority.bin"`
  - 3.121. `.INCDIR "/usr/programming/gb/include/"`
  - 3.122. `.INCLUDE "cgb_hardware.i"`
  - 3.123. `.INDEX 8`
  - 3.124. `.INPUT NAME`
  - 3.125. `.LICENSEECODENEW "1A"`
  - 3.126. `.LICENSEECODEOLD $1A`
  - 3.127. `.LONG $102030, $405060`
  - 3.128. `.LOROM`
  - 3.129. `.LYNXHEADER`
  - 3.130. `.MACRO TEST`
  - 3.131. `.MEMORYMAP`
  - 3.132. `.NAME "NAME OF THE ROM"`
  - 3.133. `.NEXTU name`
  - 3.134. `.NINTENDOLOGO`
  - 3.135. `.NOWDC`
  - 3.136. `.ORG $150`
  - 3.137. `.ORGA $150`
  - 3.138. `.OUTNAME "other.o"`
  - 3.139. `.PRINT "Numbers 1 and 10: ", DEC 1, " $", HEX 10, "\n"`
  - 3.140. `.PRINTT "Here we are...\n"`
  - 3.141. `.PRINTV DEC DEBUG+1`
  - 3.142. `.RAMSECTION "Vars" BASE $7E BANK 0 SLOT 1 ALIGN 256 OFFSET 32`
  - 3.143. `.RAMSIZE 0`
  - 3.144. `.REDEF IF $0F`
  - 3.145. `.REDEFINE IF $0F`
  - 3.146. `.REPEAT 6`
  - 3.147. `.REPT 6`
  - 3.148. `.ROMBANKMAP`
  - 3.149. `.ROMBANKS 2`
  - 3.150. `.ROMBANKSIZE $4000`
  - 3.151. `.ROMDMG`
  - 3.152. `.ROMGBCONLY`
  - 3.153. `.ROMGBC`
  - 3.154. `.ROMSGB`
  - 3.155. `.ROMSIZE 1`
  - 3.156. `.ROW $ff00, 1, "3"`
  - 3.157. `.SDSCTAG 1.0, "DUNGEON MAN", "A wild dungeon exploration game", "Ville Helin"`
  - 3.158. `.SECTION "Init" FORCE`
  - 3.159. `.SEED 123`
  - 3.160. `.SEEDRANDOM`
  - 3.161. `.SHIFT`
  - 3.162. `.SLOT 1`
  - 3.163. `.SLOWROM`
  - 3.164. `.SMC`
  - 3.165. `.NGHEADER`
  - 3.166. `.NGSOFTDIP`
  - 3.167. `.NGVECTORS`
  - 3.168. `.MDVECTORS`
  - 3.169. `.MCDHEADER`
  - 3.170. `.MCDSPHEADER`
  - 3.171. `.SMDHEADER`
  - 3.172. `.SMSHEADER`
  - 3.173. `.SMSTAG`
  - 3.174. `.SNESEMUVECTOR`
  - 3.175. `.SNESHEADER`
  - 3.176. `.SNESNATIVEVECTOR`
  - 3.177. `.STRINGMAP script "Hello\n"`
  - 3.178. `.STRINGMAPTABLE script "script.tbl"`
  - 3.179. `.STRUCT enemy_object`
  - 3.180. `.SYM SAUSAGE`
  - 3.181. `.SYMBOL SAUSAGE`
  - 3.182. `.TABLE byte, word, byte`
  - 3.183. `.UNBACKGROUND $1000 $1FFF`
  - 3.184. `.UNDEF DEBUG`
  - 3.185. `.UNDEFINE DEBUG`
  - 3.186. `.UNION name`
  - 3.187. `.VERSION 1`
  - 3.188. `.WDC`
  - 3.189. `.WHILE COUNTER > 0`
  - 3.190. `.WORD 16000, 10, 255`
- 4. Assembler Syntax
  - 4.1. Case Sensitivity
  - 4.2. Comments
  - 4.3. Line splitting
  - 4.4. Using Commas
  - 4.5. Labels
  - 4.6. Number Types
  - 4.7. Strings
  - 4.8. Substitution
  - 4.9. Mnemonics
  - 4.10. Brackets?
- 5. Error Messages
- 6. Supported ROM/RAM/Cartridge Types (WLA-GB)
  - 6.1. ROM Size
  - 6.2. RAM Size
  - 6.3. Cartridge Type
- 7. eZ80 Support
  - 7.1. ADL Mode And Suffixes
  - 7.2. Instruction Coverage
  - 7.3. Agon MOS Binaries
- 8. Cx4 Notes
  - 8.1. Program Page Model
  - 8.2. Labels And Operands
  - 8.3. Recommended Pattern
  - 8.4. Practical Notes
- 9. SH-2 support
- 10. Sega 32X support
  - 10.1. Memory maps
  - 10.2. Include files
  - 10.3. ROM layout notes
- 11. Bugs
- 12. Files
  - 12.1. `tests`
  - 12.2. `tests/gb-z80/lib`
  - 12.3. `memorymaps`
- 13. Functions
  - 13.1. User defined functions
  - 13.2. Built-in functions
  - 13.3. Examples of functions
  - 13.4. Keywords
- 14. Temporary Files
- 15. Compiling
  - 15.1. Compiling Object Files
  - 15.2. Compiling Library Files
- 16. Linking
- 17. Arithmetics
- 18. Binary to DB Conversion
- 19. Things you should know about coding for…
  - 19.1. Z80
  - 19.2. 6502
  - 19.3. 65C02
  - 19.4. 65CE02
  - 19.5. 65816
  - 19.6. MC68000
  - 19.7. HUC6280
  - 19.8. SPC-700
  - 19.9. Pocket Voice (GB-Z80)
  - 19.10. GB-Z80
- 20. WLA Flags
- 21. Extra compile time definitions
- 22. Good things to know about WLA
- 23. WLA DX’s architectural overview
  - 23.1. WLA
  - 23.2. WLALINK
- 24. WLA Symbols
  - 24.1. WLA Symbol Version History
  - 24.2. Information For Emulator Developers
- 25. Legal Note

- 1. Manpage: WLA-LINK
  - 1.1. SYNOPSIS
  - 1.2. OPTIONS
  - 1.3. DESCRIPTION
  - 1.4. EXAMPLES
- 2. Manpage: WLA-CPU
  - 2.1. SYNOPSIS
  - 2.2. OPTIONS
  - 2.3. DESCRIPTION
  - 2.4. EXAMPLES
- 3. Manpage: WLAB
  - 3.1. SYNOPSIS
  - 3.2. OPTIONS
  - 3.3. DESCRIPTION
  - 3.4. EXAMPLES

# 1. Introduction

The history behind WLA DX, from the original author, Ville Helin:

> I wrote this because I had never written an assembler before and I really needed a macro assembler which could compile the GB-Z80 code I wrote. ;) Gaelan Griffin needed real Z80 support for his SMS projects so I thought I could write WLA to be a little more open and nowadays it supports all the Z80 systems you can think of. You’ll just have to define the memorymap of the destination machine for your project. After fixing some bugs I thought I could add support for 6502 systems so all NES-people would get their share of WLA as well. After finishing that few people said they’d like 65816 support (they had SNES developing in mind) so I added support for that. And then I thought I should write a 6510 version of WLA as well…

> This is my ideal GB-Z80 macro assembler (not in final form, not yet). ;) Tastes differ. Thus WLA! Notice that WLA was initially made for Game Boy developers so the GB-Z80 version and the rest differ a little.

Good to know about WLA DX:

Almost all rules that apply to Z80 source code processing with WLA DX apply also to 6502, 65C02, 65CE02, 65816, 6800, 6801, 6809, 8008, 8080, HUC6280, SPC-700 and SuperFX.

About the names: WLA DX means all the tools covered in this documentation. So WLA DX includes WLA GB-Z80/Cx4/Z80/Z80N/eZ80/6502/65C02/65CE02/65816/68000/6800/ 6801/6809/8008/8080/HUC6280/SPC-700/SuperFX macro assembler (what a horribly long name), WLAB, and WLALINK GB-Z80/Cx4/Z80/Z80N/eZ80/6502/65C02/65CE02/65816/68000/6800/ 6801/6809/8008/8080/HUC6280/SPC-700/SuperFX linker. We use plain WLA to refer to the macro assembler in this document.

There was WLAD, an GB-Z80 dissassembler, but it has been discontinued and removed from the project and the documentation.

Currently WLA can also be used as a patch tool. Just include the original ROM image into the project with `.BACKGROUND` and insert e.g., `OVERWRITE .SECTION` s to patch the desired areas. Output the data into a new ROM image and there you have it. 100% readable (asm coded) patches are reality!

Note that you can directly compile only object and library files. You must use WLALINK to link these (or only one, if you must) into a ROM/program file.

WLA DX’s old homepage: http://www.villehelin.com/wla.html
WLA DX’s new homepage: https://github.com/vhelin/wla-dx

# 2. Quickstart

Every assembly file needs to begin with the definition of `.MEMORYMAP` and `.ROMBANKMAP`. You can put these inside a separate file that is included at the beginning of the assembly files. Here’s an example:

    .MEMORYMAP
    DEFAULTSLOT 1
    SLOT 0 START $0000 SIZE $2000
    SLOT 1 START $2000 SIZE $2000
    .ENDME

    .ROMBANKMAP
    BANKSTOTAL 2
    BANKSIZE $2000
    BANKS 8
    .ENDRO

Right after these, before any code is written, you should define bank, slot and org:

    .BANK 0 SLOT 0
    .ORGA $0000

Now you are ready to start programming!

The next step would be creating a linkfile for the linker as after the assembly files go through the assembler they need to be linked. Here is a minimal example of a linkfile when your project has just main.s (that has been assembled into main.o):

    [objects]
    main.o

Give this to the linker and you’ll get the final binaries.

# 3. Assembler Directives

Here’s the order in which the data is placed into the output:

1. Data and group 3 directives outside sections.

2. Group 2 directives.

3. Data and group 3 directives inside sections.

4. Group 1 directives.

ALL | All, GB-Z80, Cx4, Z80, Z80N, eZ80, 6502, 65C02, 65CE02, 65816, HUC6280, SPC-700, 68000, 6800, 6801, 6809, 8008, 8080 and SuperFX versions apply.
GB | Only the GB-Z80 version applies.
GB8 | Only the GB-Z80 and 65816 versions apply.
Z80 | Only the Z80 version applies.
EZ8 | Only the eZ80 version applies.
658 | Only the 65816 version applies.
68K | Only the 68000 version applies.
680 | Only the 6800, 6801 and 6809 versions apply.
800 | Only the 8008 version applies.
808 | Only the 8080 version applies.
SPC | Only the SPC-700 version applies.
SFX | Only the SuperFX version applies.
650 | Only the 6502 version applies.
65x | Only the 6502, 65C02, 65CE02, 65816 and HUC6280 versions apply.
65C | Only the 65C02 version applies.
!GB | All but the GB-Z80 versions apply.

Group 1:

GB | `.COMPUTEGBCHECKSUM`
68K | `.COMPUTESMDCHECKSUM`
Z80 | `.COMPUTESMSCHECKSUM`
658 | `.COMPUTESNESCHECKSUM`
Z80 | `.SDSCTAG 1.0, "DUNGEON MAN", "A wild dungeon exploration game", "Ville Helin"`
Z80 | `.SMSTAG`

Group 2:

GB | `.CARTRIDGETYPE 1`
GB | `.COMPUTEGBCOMPLEMENTCHECK`
GB | `.COUNTRYCODE 1`
GB | `.DESTINATIONCODE 1`
ALL | `.EMPTYFILL $C9`
658 | `.ENDEMUVECTOR`
68K | `.ENDMCDHEADER`
68K | `.ENDMCDSPHEADER`
68K | `.ENDMDVECTORS`
68K | `.ENDNG`
68K | `.ENDNGSOFTDIP`
68K | `.ENDNGVECTORS`
650 | `.ENDINES`
65C | `.ENDLYNX`
658 | `.ENDNATIVEVECTOR`
658 | `.ENDSNES`
658 | `.EXHIROM`
ALL | `.EXPORT work_x`
658 | `.FASTROM`
GB | `.GBHEADER`
658 | `.HIROM`
650 | `.INESHEADER`
GB | `.LICENSEECODENEW "1A"`
GB | `.LICENSEECODEOLD $1A`
658 | `.LOROM`
65C | `.LYNXHEADER`
GB8 | `.NAME "NAME OF THE ROM"`
68K | `.MCDHEADER`
68K | `.MCDSPHEADER`
68K | `.MDVECTORS`
68K | `.NGHEADER`
68K | `.NGSOFTDIP`
68K | `.NGVECTORS`
GB | `.NINTENDOLOGO`
ALL | `.OUTNAME "other.o"`
GB | `.RAMSIZE 0`
GB | `.ROMDMG`
GB | `.ROMGBC`
GB | `.ROMGBCONLY`
GB | `.ROMSGB`
GB | `.ROMSIZE 1`
658 | `.SLOWROM`
658 | `.SMC`
68K | `.SMDHEADER`
Z80 | `.SMSHEADER`
658 | `.SNESEMUVECTOR`
658 | `.SNESHEADER`
658 | `.SNESNATIVEVECTOR`
GB | `.VERSION 1`

Group 3:

65x | `.16BIT`
658 | `.24BIT`
65x | `.8BIT`
658 | `.ACCU 8`
EZ8 | `.ADL ON`
ALL | `.ADDR 16000, main, 255`
ALL | `.ALIGN 4`
ALL | `.ARRAYDB NAME MyArray INDICES '0', 0, 1`
ALL | `.ARRAYDD NAME MyArray INDICES '0', 0, 1`
ALL | `.ARRAYDEF NAME MyArray SIZE 256`
ALL | `.ARRAYDEFINE NAME MyArray SIZE 256`
ALL | `.ARRAYDL NAME MyArray INDICES '0', 0, 1`
ALL | `.ARRAYDW NAME MyArray INDICES '0', 0, 1`
ALL | `.ARRAYIN NAME MyArray INDEX 0 VALUE 10`
ALL | `.ARRAYOUT NAME MyArray INDEX 0 DEFINITION ArrayOut`
ALL | `.ASC "HELLO WORLD!"`
ALL | `.ASCIITABLE`
ALL | `.ASCSTR "HELLO WORLD!", $A`
ALL | `.ASCTABLE`
ALL | `.ASM`
ALL | `.ASSERT VALUE_1 == 1`
ALL | `.BACKGROUND "parallax.gb"`
ALL | `.BANK 0 SLOT 1`
ALL | `.BASE $80`
ALL | `.BITS 4 DATA %1011, %0100, %1010, %0101`
ALL | `.BLOCK "Block1"`
ALL | `.BR`
ALL | `.BREAK`
ALL | `.BREAKPOINT`
ALL | `.BYT 100, $30, %1000, "HELLO WORLD!"`
ALL | `.CONTINUE`
ALL | `.DATA $ff00, 2`
ALL | `.DB 100, $30, %1000, "HELLO WORLD!"`
ALL | `.DBCOS 0.2, 10, 3.2, 120, 1.3`
ALL | `.DBM filtermacro 1, 2, "encrypt me"`
ALL | `.DBRND 20, 0, 10`
ALL | `.DBSIN 0.2, 10, 3.2, 120, 1.3`
ALL | `.DD $1ffffff, $2000000`
ALL | `.DDM filtermacro 1, 2, 3`
ALL | `.DEF IF $FF0F`
ALL | `.DEFINE IF $FF0F`
ALL | `.DELFUNCTION SUM_AB`
ALL | `.DELMACRO TEST`
ALL | `.DL $102030, $405060`
ALL | `.DLM filtermacro 1, 2, 3`
ALL | `.DS 256, $10`
ALL | `.DSB 256, $10`
ALL | `.DSD 256, $1ffffff`
ALL | `.DSL 16, $102030`
ALL | `.DSTRUCT waterdrop INSTANCEOF water DATA "tingle", 40, 120`
ALL | `.DSW 128, 20`
ALL | `.DW 16000, 10, 255`
ALL | `.DWCOS 0.2, 10, 3.2, 1024, 1.3`
ALL | `.DWM filtermacro 1, 2, 3`
ALL | `.DWRND 20, 0, 10`
ALL | `.DWSIN 0.2, 10, 3.2, 1024, 1.3`
ALL | `.ELIF defined(DEBUG) && VERSION > 110`
ALL | `.ELSE`
ALL | `.ENDA`
ALL | `.ENDASM`
ALL | `.ENDB`
ALL | `.ENDBITS`
ALL | `.ENDE`
ALL | `.ENDIF`
ALL | `.ENDM`
ALL | `.ENDME`
ALL | `.ENDR`
ALL | `.ENDRO`
ALL | `.ENDS`
ALL | `.ENDST`
ALL | `.ENDU`
ALL | `.ENUM $C000`
ALL | `.ENUMID ID_1 0`
ALL | `.EQU IF $FF0F`
ALL | `.FAIL "THE EYE OF MORDOR HAS SEEN US!"`
ALL | `.FARADDR main, irq_1`
ALL | `.FCLOSE FP_DATABIN`
ALL | `.FILTER filtermacro 1, 2, "encrypt me"`
ALL | `.FOPEN "data.bin" FP_DATABIN`
ALL | `.FREAD FP_DATABIN DATA`
ALL | `.FSEEK FP_DATABIN 10 START`
ALL | `.FSIZE FP_DATABIN SIZE`
ALL | `.FTELL FP_DATABIN POSITION`
ALL | `.FUNCTION SUM_AB(varA,varB)`
ALL | `.HEX "a0A0ffDE"`
ALL | `.IF DEBUG == 2`
ALL | `.IFDEF IF`
ALL | `.IFDEFM \2`
ALL | `.IFEQ DEBUG 2`
ALL | `.IFEXISTS "main.s"`
ALL | `.IFGR DEBUG 2`
ALL | `.IFGREQ DEBUG 1`
ALL | `.IFLE DEBUG 2`
ALL | `.IFLEEQ DEBUG 1`
ALL | `.IFNDEF IF`
ALL | `.IFNDEFM \2`
ALL | `.IFNEQ DEBUG 2`
ALL | `.INC "cgb_hardware.i"`
ALL | `.INCBIN "sorority.bin"`
ALL | `.INCDIR "/usr/programming/gb/include/"`
ALL | `.INCLUDE "cgb_hardware.i"`
658 | `.INDEX 8`
ALL | `.INPUT NAME`
ALL | `.LONG $102030, $405060`
ALL | `.MACRO TEST`
ALL | `.MEMORYMAP`
ALL | `.NEXTU name`
658 | `.NOWDC`
ALL | `.ORG $150`
ALL | `.ORGA $150`
ALL | `.PRINT "Numbers 1 and 10: ", DEC 1, " $", HEX 10, "\n"`
ALL | `.PRINTT "Here we are...\n"`
ALL | `.PRINTV DEC DEBUG+1`
ALL | `.RAMSECTION "Vars" BASE $7E BANK 0 SLOT 1 ALIGN 256 OFFSET 32`
ALL | `.REDEF IF $F`
ALL | `.REDEFINE IF $F`
ALL | `.REPEAT 6`
ALL | `.REPT 6`
ALL | `.ROMBANKMAP`
ALL | `.ROMBANKS 2`
ALL | `.ROMBANKSIZE $4000`
ALL | `.ROW $ff00, 1, "3"`
ALL | `.SECTION "Init" FORCE`
ALL | `.SEED 123`
ALL | `.SEEDRANDOM`
ALL | `.SHIFT`
ALL | `.SLOT 1`
ALL | `.STRINGMAP script "Hello\n"`
ALL | `.STRINGMAPTABLE script "script.tbl"`
ALL | `.STRUCT enemy_object`
ALL | `.SYM SAUSAGE`
ALL | `.SYMBOL SAUSAGE`
ALL | `.TABLE byte, word, byte`
ALL | `.UNBACKGROUND $1000 $1FFF`
ALL | `.UNDEF DEBUG`
ALL | `.UNDEFINE DEBUG`
ALL | `.UNION name`
658 | `.WDC`
ALL | `.WHILE COUNTER > 0`
ALL | `.WORD 16000, 10, 255`

Descriptions:

## 3.1. `.16BIT`

Analogous to `.8BIT`. `.16BIT` forces all addresses and immediate values to be expanded into 16-bit range, when possible, that is:

    LSR 11       ; $46 $0B

That would be the case, normally, but after `.16BIT` it becomes:

    LSR 11       ; $4E $0B $00

This is not a compulsory directive.

## 3.2. `.24BIT`

Analogous to `.8BIT` and `.16BIT`. `.24BIT` forces all addresses to be expanded into 24-bit range, when possible, that is:

    AND $11       ; $25 $11

That would be the case, normally, but after `.24BIT` it becomes:

    AND $11       ; $2F $11 $00 $00

If it is not possible to expand the address into `.24BIT` range, then WLA tries to expand it into 16-bit range.

This is not a compulsory directive.

## 3.3. `.ADL ON`

For WLA-eZ80, `.ADL ON` makes Z80-style 16-bit immediate and address operands assemble as 24-bit values where the eZ80 instruction encoding allows it. `.ADL OFF` returns to the default Z80-compatible 16-bit behavior.

The per-instruction suffixes `.SIS`, `.LIS`, `.SIL` and `.LIL` emit the matching eZ80 mode prefix byte. `.SIS` and `.LIS` force a short immediate for that instruction; `.SIL` and `.LIL` force a long immediate. `.S` and `.L` are accepted as short forms for instruction-mode overrides without an immediate operand.

This is not a compulsory directive.

## 3.4. `.8BIT`

There are a few mnemonics that look identical, but take different sized arguments. Here’s a list of such 6502 mnemonics:

ADC, AND, ASL, BIT, CMP, CPX, CPY, DEC, EOR, INC, LDA, LDX, LDY, ORA, ROL, SBC, STA, STX and STY.

For example:

    LSR 11       ; $46 $0B
    LSR $A000    ; $4E $00 $A0

The first one could also be:

    LSR 11       ; $4E $0B $00

`.8BIT` is here to help WLA to decide to choose which one of the opcodes it selects. When you give `.8BIT` (default) no 8-bit address/value is expanded to 16-bits.

By default WLA uses the smallest possible size. This is true also when WLA finds a computation it can’t solve right away. WLA assumes the result will be inside the smallest possible bounds, which depends on the type of the mnemonic.

You can also use the fixed argument size versions of such mnemonics by giving the size with the operand (i.e., operand hinting). Here are few examples:

    LSR 11.B   ; $46 $0B
    LSR 11.W   ; $4E $0B $00

In WLA-65816 `.ACCU` / `.INDEX` / `SEP` / `REP` override `.8BIT` / `.16BIT`/`.24BIT` when considering the immediate values, so be careful. Still, operand hints override all of these, so use them to be sure.

To hint that the operand fits 8 bits and also take the lowest 8 bits of the operand do this:

    STA ZEROPAGE0.#B  ; $85 $00

This is not a compulsory directive.

## 3.5. `.ACCU 8`

Forces WLA to override the accumulator size given with `SEP` / `REP`. `.ACCU` doesn’t produce any code, it only affects the way WLA interprets the immediate values (8 for 8 bit operands, 16 for 16 bit operands) for opcodes dealing with the accumulator.

So after giving `.ACCU 8`:

    AND #6

will produce `$29 $06`, and after giving `.ACCU 16`:

    AND #6

will yield `$29 $00 $06`.

Note that `SEP` / `REP` again will in turn reset the accumulator/index register size.

This is not a compulsory directive.

## 3.6. `.ADDR 16000, main, 255`

`.ADDR` is an alias for `.DW`.

This is not a compulsory directive.

## 3.7. `.ALIGN 4`

Makes it so that on the next line the address is a multiple of the supplied value. Currently this directive can only be given outside `.SECTION` s or inside FORCE `.SECTION` s or inside `.SECTION` s that have ALIGN that is a multiple of the `.ALIGN` here.

This is not a compulsory directive.

## 3.8. `.ARRAYDB NAME MyArray INDICES '0', 0, 1`

This is the same as `.DB`, but defines bytes by reading indexed values from the given array. In the example the indices are ‘0’ (48), 0 and 1.

`NAME` and `INDICES` are optional so this works also:

    .ARRAYDB MyArray '0', 0, 1

If you supply `.ARRAYDB` a string as indices, each character is used as an index:

    .ARRAYDB NAME MyArray INDICES "MAP THIS!"

This is not a compulsory directive.

## 3.9. `.ARRAYDD NAME MyArray INDICES '0', 0, 1`

`.ARRAYDD` works the same way as `.ARRAYDB`, but defines 32-bit double words.

This is not a compulsory directive.

## 3.10. `.ARRAYDEF NAME MyArray SIZE 256`

`.ARRAYDEF` is an alias for `.ARRAYDEFINE`.

This is not a compulsory directive.

## 3.11. `.ARRAYDEFINE NAME MyArray SIZE 256`

Defines an array called MyArray, and its initial size is 256 items. Each item is an ANSI C89 int (32-bit). The array can be written into using directive `.ARRAYIN` and it can be read from using directive `.ARRAYOUT`. This array exists only in WLA’s memory and during assembling, but it can be used for e.g., mapping parts of ASCII table into e.g., 4 bits:

    // define a too small array for mapping "0123456789" -> 4-bits
    // it gets enlarged by out-of-bounds .ARRAYINs later...
    .ARRAYDEFINE NAME MyArray SIZE 4

    // define the mapping
    .ARRAYIN NAME MyArray INDEX '0' VALUE %0000
    .ARRAYIN NAME MyArray INDEX '1' VALUE %0001
    .ARRAYIN NAME MyArray INDEX '2' VALUE %0010
    .ARRAYIN NAME MyArray INDEX '3' VALUE %0011
    .ARRAYIN NAME MyArray INDEX '4' VALUE %0100
    .ARRAYIN NAME MyArray INDEX '5' VALUE %0101
    .ARRAYIN NAME MyArray INDEX '6' VALUE %0110
    .ARRAYIN NAME MyArray INDEX '7' VALUE %0111
    .ARRAYIN NAME MyArray INDEX '8' VALUE %1000
    .ARRAYIN NAME MyArray INDEX '9' VALUE %1001

    // map!
    .ARRAYOUT NAME MyArray INDEX '6' DEFINITION Mapping
    .DB Mapping
    .ARRAYOUT NAME MyArray INDEX '6' DEFINITION Mapping
    .DB Mapping
    .ARRAYOUT NAME MyArray INDEX '8' DEFINITION Mapping
    .DB Mapping
    .ARRAYOUT NAME MyArray INDEX '2' DEFINITION Mapping
    .DB Mapping
    .ARRAYOUT NAME MyArray INDEX '7' DEFINITION Mapping
    .DB Mapping
    .ARRAYOUT NAME MyArray INDEX '5' DEFINITION Mapping
    .DB Mapping

You can also do the mapping using e.g., `.ARRAYDB`:

    .ARRAYDB NAME MyArray INDICES '6', '6', '8', '2', '7', '5'
    .ARRAYDB NAME MyArray INDICES "668275"

And create the mapping using only one `.ARRAYIN`:

    .ARRAYIN NAME MyArray INDEX '0' VALUES %0000, %0001, \
        %0010, %0011, %0100, %0101, %0110, %0111, %1000, \
        %1001

Note that keywords NAME and SIZE are optional, so this works also:

    .ARRAYDEFINE MyArray 4

This is not a compulsory directive.

## 3.12. `.ARRAYDL NAME MyArray INDICES '0', 0, 1`

`.ARRAYDL` works the same way as `.ARRAYDB`, but defines 24-bit long words.

This is not a compulsory directive.

## 3.13. `.ARRAYDW NAME MyArray INDICES '0', 0, 1`

`.ARRAYDW` works the same way as `.ARRAYDB`, but defines 16-bit words.

This is not a compulsory directive.

## 3.14. `.ARRAYIN NAME MyArray INDEX 0 VALUE 10`

Writes a value into an array defined using `.ARRAYDEFINE`. Check out `.ARRAYDEFINE` for a nice example. The value needs to be known at the time the assembler is parsing through the code.

Keywords NAME, INDEX and VALUE are optional so this works also:

    .ARRAYIN MyArray 0 10

This is not a compulsory directive.

## 3.15. `.ARRAYOUT NAME MyArray INDEX 0 DEFINITION ArrayOut`

Reads a value from an array defined using `.ARRAYDEFINE`. Check out `.ARRAYDEFINE` for a nice example. The value is stored in definition `ArrayOut` in the example.

Keywords NAME, INDEX and DEFINITION are optional so this works also:

    .ARRAYOUT MyArray 0 ArrayOut

This is not a compulsory directive.

## 3.16. `.ASC "HELLO WORLD!"`

`.ASC` is an alias for `.DB`, but if you use `.ASC` it will remap the characters using the mapping given via `.ASCIITABLE`.

You can also use ASC(‘?’) to map individual characters in the code

    .DB ASC('A'), ASC('B'), ASC(10), ASC('\r')

and

> LD A, ASC(‘A’)

This is not a compulsory directive.

## 3.17. `.ASCIITABLE`

`.ASCIITABLE`’s only purpose is to provide character mapping for `.ASC` and `ASC('?')`. Take a look at the example:

    .ASCIITABLE
    MAP "A" TO "Z" = 0
    MAP "!" = 90
    .ENDA

Here we set such a mapping that character `A` is equal to `0`, `B` is equal to `1`, `C` is equal to `2`, and so on, and `!` is equal to `90`.

After you’ve given the `.ASCIITABLE`, use `.ASC` to define bytes using this mapping (`.ASC` is an alias for `.DB`, but with `.ASCIITABLE` mapping). For example, `.ASC "ABZ"` would define bytes `0`, `1` and `25` in our previous example.

Note that the following works as well:

    .ASCIITABLE
    MAP 'A' TO 'Z' = 0
    MAP 65 = 90          ; 65 is the decimal for ASCII 'A'
    .ENDA

Also note that the characters that are not given any mapping in `.ASCIITABLE` map to themselves (i.e., `2` maps to `2` in our previous example, etc.).

This is not a compulsory directive.

## 3.18. `.ASCSTR "HELLO WORLD!", $A`

`.ASCSTR` is the same as `.ASC`, but it maps only supplied strings. All given bytes are not touched.:

    .ASCSTR "HELLO WORLD!", $A

In this example the string “HELLO WORLD!” is mapped using the mapping given via `.ASCIITABLE`, but the last byte $A is left as it is.

This is not a compulsory directive.

## 3.19. `.ASCTABLE`

`.ASCTABLE` is an alias for `.ASCIITABLE`.

This is not a compulsory directive.

## 3.20. `.ASM`

Tells WLA to start assembling. Use `.ASM` to continue the work which has been disabled with `.ENDASM`. `.ASM` and `.ENDASM` can be used to mask away big blocks of code. This is analogous to the ANSI C -comments (`/*...*/`), but `.ASM` and `.ENDASM` can be nested, unlike the ANSI C -counterpart.

This is not a compulsory directive.

## 3.21. `.ASSERT VALUE_1 == 1`

`.ASSERT` takes a condition, and if it’s evaluated to be true, nothing happens. If it’s false, then assembling ends right there in an error.

`.ASSERT` also accepts an optional action and message:

    .ASSERT VALUE_1 == 1, ERROR, "VALUE_1 must be 1."
    .ASSERT VALUE_1 == 1, WARNING, "VALUE_1 should be 1."
    .ASSERT label_end-label_start == 3, LDERROR, "Unexpected linked size."
    .ASSERT label_end-label_start == 3, LDWARNING, "Unexpected linked size."

`ERROR` is the default action and preserves the immediate fatal behavior. `WARNING` is evaluated by the assembler and lets assembly continue. `LDERROR` and `LDWARNING` are evaluated by WLALINK after labels, sections and `_sizeof_` definitions have been resolved.

This is not a compulsory directive.

## 3.22. `.BACKGROUND "parallax.gb"`

This chooses an existing ROM image (`parallax.gb` in this case) as a background data for the project. You can overwrite the data with `OVERWRITE` sections only, unless you first clear memory blocks with `.UNBACKGROUND` after which there’s room for other sections as well.

Note that `.BACKGROUND` can be used only when compiling an object file.

`.BACKGROUND` is useful if you wish to patch an existing ROM image with new code or data.

This is not a compulsory directive.

## 3.23. `.BANK 0 SLOT 1`

Defines the ROM bank and the slot it is inserted into in the memory. You can also type the following:

    .BANK 0

This tells WLA to move into BANK 0 which will be put into the `DEFAULTSLOT` of `.MEMORYMAP`.

Every time you use `.BANK`, supply `.ORG` / `.ORGA` as well, just to make sure WLA calculates addresses correctly.

This is a compulsory directive.

## 3.24. `.BASE $80`

Defines the base value for the bank number (used only in 24-bit addresses and when getting a label’s bank number with `:`). Here are few examples of how to use `.BASE` (both examples assume the label resides in the first ROM bank):

    .BASE $00
    label1:
    .BASE $80
    label2:

      JSL label1   ; if label1 address is $1234, this will assemble into
                   ; JSL $001234
      JSL label2   ; label2 is also $1234, but this time the result will be
                   ; JSL $801234

`.BASE` defaults to `$00`. Note that the address of the label will also contribute to the bank number (bank number == `.BASE` + ROM bank of the label).

On 65816, use `.LOROM`, `.HIROM` or `.EXHIROM` to define the ROM mode.

`.BASE` can also given inside a `.SECTION`, but after `.ENDS` the base value before the `.SECTION` is returned.

This is not a compulsory directive.

## 3.25. `.BITS 4 DATA %1011, %0100, %1010, %0101`

This is the same as `.DB`, but defines bits (1-32). Consecutive `.BITS` will supply bits to the same bitstream, so don’t do any stream breaking `.DB` calls or anything that defines data. `DATA` is optional. Give

> .BITS START

to start a new bitstream.

Here’s an example of how to define two bytes worth of bits:

    .BITS 6 CABBAGE, %011110    ; CABBAGE == %110011
    .BITS 4 8+2                 ; 8 + 2 == %1010
    .BITS 4 %1011
    .ENDBITS                    ; writes the final byte in the bitstream
                                ; and resets the counters

If your `.BITS` bitstream doesn’t define exactly a multiple of 8 bits, the remaining bits are set to zero. Remember to issue `.ENDBITS` after the last `.BITS`.

Currently the bits are written from most significant bit to the least significant bit, so our previous example would give us (consecutive) bytes %11001101, %11101010 and %10110000 ($CD, $EA and $B0).

This is not a compulsory directive.

## 3.26. `.BLOCK "Block1"`

Begins a block (called `Block1` in the example). These blocks have only one function: to display the number of bytes they contain. When you embed such a block into your code, WLA displays its size when it assembles the source file.

Use `.ENDB` to terminate a `.BLOCK`. Note that you can nest `.BLOCK` s.

This is not a compulsory directive.

## 3.27. `.BR`

Inserts a breakpoint that behaves like a `.SYM` without a name. Breakpoints can only be seen in WLALINK’s symbol file.

This is not a compulsory directive.

## 3.28. `.BREAK`

Exits the active `.REPEAT` or `.WHILE`.

This is not a compulsory directive.

## 3.29. `.BREAKPOINT`

`.BREAKPOINT` is an alias for `.BR`.

This is not a compulsory directive.

## 3.30. `.BYT 100, $30, %1000, "HELLO WORLD!"`

`.BYT` is an alias for `.DB`.

This is not a compulsory directive.

## 3.31. `.CARTRIDGETYPE 1`

Indicates the type of the cartridge (mapper and so on). This is a standard Gameboy cartridge type indicator value found at `$147` in a Gameboy ROM, and there this one is put to also.

This is not a compulsory directive.

## 3.32. `.COMPUTEGBCHECKSUM`

When this directive is used WLA computes the ROM checksum found at `$14E` and `$14F` in a Gameboy ROM. Note that this directive can only be used with WLA-GB.

Note that you can also write `.COMPUTECHECKSUM` (the old name for this directive), but it’s not recommended.

This is not a compulsory directive.

## 3.33. `.COMPUTEGBCOMPLEMENTCHECK`

When this directive is used WLA computes the ROM complement check found at `$14D` in a Gameboy ROM.

Note that you can still use `.COMPUTECOMPLEMENTCHECK` (the old name for this directive), but it’s not recommended.

This is not a compulsory directive.

## 3.34. `.COMPUTESMDCHECKSUM`

When this directive is used WLA computes the Sega Mega Drive ROM checksum found at `$18E`. Note that this directive works only with WLA-68000.

This is not a compulsory directive.

## 3.35. `.COMPUTESMSCHECKSUM`

When this directive is used WLA computes the ROM checksum found at `$7FFA` and `$7FFB` (or `$3FFA` - `$3FFB` is the ROM is 16KBs, or `$1FFA` - `$1FFB` for 8KB ROMs) in a SMS/GG ROM. Note that this directive can only be used with WLA-z80. Also note that the ROM size must be at least 8KBs. The checksum is calculated using bytes `0x0000` - `0x1FEF` / `0x3FEF` / `0x7FEF`.

This is not a compulsory directive.

## 3.36. `.COMPUTESNESCHECKSUM`

When this directive is used WLA computes the SNES ROM checksum and inverse checksum found at `$7FDC` - `$7FDF` (LoROM), `$FFDC` - `$FFDF` (HiROM) or `$40FFDC` - `$40FFDF` and `$FFDC` - `$FFDF` (ExHiROM). Note that this directive can only be used with WLA-65816. Also note that the ROM size must be at least 32KB for LoROM images, 64KB for HiROM images and 32.5MBit for ExHiROM.

`.LOROM`, `.HIROM` or `.EXHIROM` must be issued before `.COMPUTESNESCHECKSUM`.

This is not a compulsory directive.

## 3.37. `.CONTINUE`

Jumps to the beginning of an active `.REPEAT` or `.WHILE`.

This is not a compulsory directive.

## 3.38. `.COUNTRYCODE 1`

Indicates the country code located at `$14A` of a Gameboy ROM.

This is not a compulsory directive.

## 3.39. `.DATA $ff00, 2`

Defines bytes after a .TABLE has been used to define the format. An alternative way of defining bytes to .DB/.DW.

Note that when you use .DATA you can give as many items .TABLE defines. The next time you’ll use .DATA you’ll continue from the point the previous .DATA ended.

Examples:

    .TABLE dsw 2, dsb 2

This defines two rows worth of bytes:

    .DATA $ff00, $aabb, $10, $20, $1020, $3040, $50, $60

This does the same:

    .DATA $ff00, $aabb
    .DATA $10, $20
    .DATA $1020, $3040
    .DATA $50, $60

This is not a compulsory directive.

## 3.40. `.DB 100, $30, %1000, "HELLO WORLD!"`

Defines bytes.

This is not a compulsory directive.

## 3.41. `.DBCOS 0.2, 10, 3.2, 120, 1.3`

Defines bytes just like `.DSB` does, only this time they are filled with cosine data. `.DBCOS` takes five arguments.

The first argument is the starting angle. Angle value ranges from `0` to `359.999`…, but you can supply WLA with values that are out of the range - WLA fixes them ok. The value can be integer or float.

The second argument descibes the amount of additional angles. The example will define 11 angles.

The third argument is the adder value which is added to the angle value when next angle is calculated. The value can be integer or float.

The fourth and fifth arguments can be seen from the pseudo code below, which also describes how `.DBCOS` works. The values can be integer or float.

Remember that `cos` (and `sin`) here returns values ranging from `-1` to `1`:

    .DBCOS A, B, C, D, E

    for (B++; B > 0; B--) {
      output_data((D * cos(A)) + E)
      A = keep_in_range(A + C)
    }

This is not a compulsory directive.

## 3.42. `.DBM filtermacro 1, 2, "encrypt me"`

Defines bytes using a filter macro. All the data is passed to `filtermacro` in the first argument, one byte at a time, and the byte that actually gets defined is the value of definition `_OUT` (`_out` works as well). The second macro argument holds the offset from the beginning (the first byte) in bytes (the series being `0`, `1`, `2`, `3`, …).

Here’s an example of a filter macro that increments all the bytes by one:

    .macro increment
    .redefine _out \1+1
    .endm

This is not a compulsory directive.

## 3.43. `.DBRND 20, 0, 10`

Defines bytes, just like `.DSB` does, only this time they are filled with (pseudo) random numbers. We use the integrated Mersenne Twister to generate the random numbers. If you want to seed the random number generator, use `.SEED`.

The first parameter (`20` in the example) defines the number of random numbers we want to generate. The next two tell the range of the random numbers, i.e. min and max.

Here’s how it works:

    .DBRND A, B, C

    for (i = 0; i < A; i++)
      output_data((rand() % (C-B+1)) + B);

You can also use the following keywords to make the code clearer:

    .DBRND COUNT A MIN B MAX C

This is not a compulsory directive.

## 3.44. `.DBSIN 0.2, 10, 3.2, 120, 1.3`

Analogous to `.DBCOS`, but does `sin()` instead of `cos()`.

This is not a compulsory directive.

## 3.45. `.DD $1ffffff, $2000000`

Defines double words (four bytes each). `.DD` takes only numbers, labels and characters as input, not strings.

This is not a compulsory directive.

## 3.46. `.DDM filtermacro 1, 2, 3`

Defines 32-bit words using a filter macro. Works just like `.DBM`, `.DWM` and `.DLM`.

This is not a compulsory directive.

## 3.47. `.DEF IF $FF0F`

`.DEF` is an alias for `.DEFINE`.

This is not a compulsory directive.

## 3.48. `.DEFINE IF $FF0F`

Assigns a number or a string to a definition label.

By default all defines are local to the file where they are presented. If you want to make the definition visible to all the files in the project, use `.EXPORT` or add EXPORT to the end of .DEFINE:

    .DEFINE ID_0 0 EXPORT

WARNING: Please declare your definition lexically before using it as otherwise the assembler might make incorrect assumptions about its value and size and choose e.g. wrong opcodes and generate binary that doesn’t run properly.

Here are some examples:

    .DEFINE X 1000
    .DEFINE FILE "level01.bin"
    .DEFINE TXT1 "hello and welcome", 1, "to a new world...", 0
    .DEFINE BYTES 1, 2, 3, 4, 5
    .DEFINE COMPUTATION X+1
    .DEFINE DEFAULTV

All definitions with multiple values are marked as data strings, and `.DB` is about the only place where you can later on use them:

    .DEFINE BYTES 1, 2, 3, 4, 5
    .DB 0, BYTES, 6

is the same as:

    .DB 0, 1, 2, 3, 4, 5, 6

If you omit the definition value (in our example `DEFAULTV`), WLA will default to `0`.

Note that you must do your definition before you use it, otherwise WLA will use the final value of the definition. Here’s an example of this:

    .DEFINE AAA 10
    .DB AAA            ; will be 10.
    .REDEFINE AAA 11

but:

    .DB AAA            ; will be 11.
    .DEFINE AAA 10
    .REDEFINE AAA 11

You can also create definitions on the command line. Here’s an example of this:

    wla-gb -vl -DMOON -DNAME=john -DPRICE=100 -DADDRESS=$100 math.s

`MOON`’s value will be `0`, `NAME` is a string definition with value `john`, `PRICE`’s value will be `100`, and `ADDRESS`’s value will be `$100`.

Note that:

    .DEFINE AAA = 10   ; the same as ".DEFINE AAA 10".

works as well. And this works also:

    AAA = 10

If the name is immediately followed by `(`, `.DEFINE` creates a function just like `.FUNCTION`:

    .DEFINE SUM_AB(varA, varB) (varA + varB)

This is not a compulsory directive.

## 3.49. `.DELFUNCTION SUM_AB`

Deletes the function called `SUM_AB`.

This is not a compulsory directive.

## 3.50. `.DELMACRO TEST`

Deletes the macro called `TEST`.

This is not a compulsory directive.

## 3.51. `.DESTINATIONCODE 1`

`.DESTINATIONCODE` is an alias for `.COUNTRYCODE`.

This is not a compulsory directive.

## 3.52. `.DL $102030, $405060`

Defines long words (three bytes each). `.DL` takes only numbers, labels and characters as input, not strings.

This is not a compulsory directive.

## 3.53. `.DLM filtermacro 1, 2, 3`

Defines 24-bit words using a filter macro. Works just like `.DBM`, `.DWM` and `.DDM`.

This is not a compulsory directive.

## 3.54. `.DS 256, $10`

`.DS` is an alias for `.DSB`.

This is not a compulsory directive.

## 3.55. `.DSB 256, $10`

Defines `256` bytes of `$10`.

This is not a compulsory directive.

## 3.56. `.DSD 256, $1ffffff`

Defines `256` double words (four bytes) of `$1ffffff`.

This is not a compulsory directive.

## 3.57. `.DSL 16, $102030`

Defines `16` long words (three bytes) of `$102030`.

This is not a compulsory directive.

## 3.58. `.DSTRUCT waterdrop INSTANCEOF water VALUES`

Defines an instance of `.STRUCT` water, called waterdrop, and fills it with the given data. Before calling `.DSTRUCT` we must have defined the structure, and in this example it could be like:

    .STRUCT water
        name   ds 8
        age    db
        weight dw
    .ENDST

There are two syntaxes for `.DSTRUCT`; the new and legacy versions. To use the new syntax, put the keyword `VALUES` at the end of the first line. The old syntax uses the keyword `DATA` or none at all.

The new syntax looks like this:

    .DSTRUCT waterdrop INSTANCEOF water VALUES
        name:   .db "tingle"
        age:    .db 40
        weight: .dw 120
    .ENDST

The fields can be put in any order. Any omitted fields are set to the `.EMPTYFILL` value (`$00` by default). Any data-defining directive can be used within `.DSTRUCT`, as long as it does not exceed the size of the data it is being defined for. The only exception is `.DSTRUCT` itself, which cannot be nested.

The old syntax looks like this:

    .DSTRUCT waterdrop INSTANCEOF water DATA "tingle", 40, 120

The `DATA` and `INSTANCEOF` keywords are optional. This will assign data for each field of the struct in the order they were defined.

In either example you would get the following labels:

    waterdrop
    waterdrop.name
    waterdrop.age
    waterdrop.weight
    _sizeof_waterdrop        = 11
    _sizeof_waterdrop.name   = 8
    _sizeof_waterdrop.age    = 1
    _sizeof_waterdrop.weight = 2

The legacy syntax does not support unions; it will give an error if you attempt to define data for a union.

For the new syntax, nested structs are supported like so (assume the `water` struct is also defined:

    .STRUCT drop_pair
        waterdrops: instanceof water 2
    .ENDST

    .DSTRUCT drops INSTANCEOF drop_pair VALUES
        waterdrops.1:        .db "qwertyui" 40
                             .dw 120
        waterdrops.2.name:   .db "tingle"
        waterdrops.2.age:    .db 40
        waterdrops.2.weight: .dw 12
    .ENDST

In this case, the properties of `waterdrops.1` were defined implicitly; 8 bytes for the name, followed by a byte for the age, followed by a word for the weight. The values for `waterdrops.2` were defined in a more clear way.

In this case, `waterdrops` and `waterdrops.1` are equivalent. `waterdrops.1.name` is different, even though its address is the same, because it has a size of 8. If you attempted to do this:

    .DSTRUCT drops INSTANCEOF drop_pair VALUES
        waterdrops.1.name:   .db "qwertyui" 40
                             .dw 120
    .ENDST

It would fail, because only the 8 name bytes are available to be defined in this context, as opposed to the 11 bytes for the entire `waterdrops.1` structure.

Named unions can be assigned to in a similar way, by writing its full name with a `.` separating the union name and the field name.

The struct can be defined namelessly:

    .DSTRUCT INSTANCEOF drop_pair VALUES
        ...
    .ENDST

You can use `SIZE` to specify the size of the instance. The additional bytes are filled with `.EMPTYFILL`:

    .DSTRUCT INSTANCEOF drop_pair SIZE 128 VALUES
        ...
    .ENDST

If you don’t want to generate labels use `NOLABELS`:

    .DSTRUCT INSTANCEOF drop_pair NOLABELS VALUES
        ...
    .ENDST

Here’s another example using the legacy syntax:

    .DSTRUCT INSTANCEOF water SIZE 32 NOLABELS DATA "Ocean", 100, 16384

This is not a compulsory directive.

## 3.59. `.DSW 128, 20`

Defines `128` words (two bytes) of `20`.

This is not a compulsory directive.

## 3.60. `.DW 16000, 10, 255`

Defines words (two bytes each). `.DW` takes only numbers, labels and characters as input, not strings.

This is not a compulsory directive.

## 3.61. `.DWCOS 0.2, 10, 3.2, 1024, 1.3`

Analogous to `.DBCOS` (but defines 16-bit words).

This is not a compulsory directive.

## 3.62. `.DWM filtermacro 1, 2, 3`

Defines 16-bit words using a filter macro. Works just like `.DBM`, `.DLM` and `.DDM`.

This is not a compulsory directive.

## 3.63. `.DWRND 20, 0, 10`

Analogous to `.DBRND` (but defines words).

This is not a compulsory directive.

## 3.64. `.DWSIN 0.2, 10, 3.2, 1024, 1.3`

Analogous to `.DBCOS` (but defines 16-bit words and does `sin()` instead of `cos()`).

This is not a compulsory directive.

## 3.65. `.ELIF defined(DEBUG) && VERSION > 110`

`.ELIF` means `ELSE IF`. Can be used after an `.IF` and the likes in following fashion

    .IF VERSION == 101
      .db 1
    .ELIF VERSION == 102
      .db 2
    .ELIF VERSION == 103
      .db 3
    .ELSE
      .db $ff
    .ENDIF

This is not a compulsory directive.

## 3.66. `.ELSE`

If the previous `.IFxxx` failed then the following text until `.ENDIF` is acknowledged.

This is not a compulsory directive.

## 3.67. `.EMPTYFILL $C9`

This byte is used in filling the unused areas of the ROM file. `EMPTYFILL` defaults to `$00`.

This is not a compulsory directive.

## 3.68. `.ENDASM`

Tells WLA to stop assembling. Use `.ASM` to continue the work.

This is not a compulsory directive.

## 3.69. `.ENDA`

Ends the ASCII table.

This is not a compulsory directive, but when `.ASCIITABLE` or `.ASCTABLE` are used this one is required to terminate them.

## 3.70. `.ENDB`

Terminates `.BLOCK`.

This is not a compulsory directive, but when `.BLOCK` is used this one is required to terminate it.

## 3.71. `.ENDBITS`

Terminates `.BITS`.

This is not a compulsory directive, but when `.BITS` is used this one is required to terminate it.

## 3.72. `.ENDEMUVECTOR`

Ends definition of the emulation mode interrupt vector table.

This is not a compulsory directive, but when `.SNESEMUVECTOR` is used this one is required to terminate it.

## 3.73. `.ENDE`

Ends the enumeration.

This is not a compulsory directive, but when `.ENUM` is used this one is required to terminate it.

## 3.74. `.ENDIF`

This terminates any `.IFxxx` directive.

This is not a compulsory directive, but if you use any `.IFxxx` then you need also to apply this.

## 3.75. `.ENDME`

Terminates `.MEMORYMAP`.

This is not a compulsory directive, but when `.MEMORYMAP` is used this one is required to terminate it.

## 3.76. `.ENDM`

Ends a `.MACRO`.

This is not a compulsory directive, but when `.MACRO` is used this one is required to terminate it.

## 3.77. `.ENDNATIVEVECTOR`

Ends definition of the native mode interrupt vector table.

This is not a compulsory directive, but when `.SNESNATIVEVECTOR` is used this one is required to terminate it.

## 3.78. `.ENDNG`

Ends the Neo Geo cartridge header definition.

This is not a compulsory directive, but when `.NGHEADER` is used this one is required to terminate it.

## 3.79. `.ENDNGSOFTDIP`

Ends the Neo Geo soft-DIP / configuration-menu block definition.

This is not a compulsory directive, but when `.NGSOFTDIP` is used this one is required to terminate it.

## 3.80. `.ENDNGVECTORS`

Ends the Neo Geo interrupt-vector stub table definition.

This is not a compulsory directive, but when `.NGVECTORS` is used this one is required to terminate it.

## 3.81. `.ENDRO`

Ends the rom bank map.

This is not a compulsory directive, but when `.ROMBANKMAP` is used this one is required to terminate it.

## 3.82. `.ENDR`

Ends the `.REPEAT` or `.WHILE`.

This is not a compulsory directive, but when `.REPEAT` or `.WHILE` is used this one is required to terminate it.

## 3.83. `.ENDSNES`

This ends the SNES header definition.

This is not a compulsory directive, but when `.SNESHEADER` is used this one is required to terminate it.

## 3.84. `.ENDST`

Ends the structure definition.

This is not a compulsory directive, but when `.STRUCT` is used this one is required to terminate it.

## 3.85. `.ENDS`

Ends the section.

This is not a compulsory directive, but when `.SECTION` or `.RAMSECTION` is used this one is required to terminate it.

## 3.86. `.ENDU`

Ends the current union.

## 3.87. `.ENUM $C000`

Starts enumeration from `$C000`. Very useful for defining variables.

To start a descending enumeration, put `DESC` after the starting value. WLA defaults to `ASC` (ascending enumeration).

You can also add `EXPORT` after these if you want to export all the generated definitions automatically.

Here’s an example of `.ENUM`:

    .STRUCT mon                ; check out the documentation on
    name ds 2                  ; .STRUCT
    age  db
    .ENDST

    .ENUM $A000
    _scroll_x DB               ; db  - define byte (byt and byte work also)
    _scroll_y DB
    player_x: DW               ; dw  - define word (word works also)
    player_y: DW
    map_01:   DS  16           ; ds  - define size (bytes)
    map_02    DSB 16           ; dsb - define size (bytes)
    map_03    DSW  8           ; dsw - define size (words)
    monster   INSTANCEOF mon 3 ; three instances of structure mon
    dragon    INSTANCEOF mon   ; one mon
    .ENDE

Previous example transforms into following definitions:

    .DEFINE _scroll_x      $A000
    .DEFINE _scroll_y      $A001
    .DEFINE player_x       $A002
    .DEFINE player_y       $A004
    .DEFINE map_01         $A006
    .DEFINE map_02         $A016
    .DEFINE map_03         $A026
    .DEFINE monster        $A036
    .DEFINE monster.1      $A036
    .DEFINE monster.1.name $A036
    .DEFINE monster.1.age  $A038
    .DEFINE monster.2      $A039
    .DEFINE monster.2.name $A039
    .DEFINE monster.2.age  $A03B
    .DEFINE monster.3      $A03C
    .DEFINE monster.3.name $A03C
    .DEFINE monster.3.age  $A03E
    .DEFINE dragon         $A03F
    .DEFINE dragon.name    $A03F
    .DEFINE dragon.age     $A041

`DB`, `DW`, `DS`, `DSB`, `DSW` and `INSTANCEOF` can also be in lowercase. You can also use a dotted version of the symbols, but it doesn’t advance the memory address. Here’s an example:

    .ENUM $C000 DESC EXPORT
    bigapple_h db
    bigapple_l db
    bigapple:  .dw
    .ENDE

And this is what is generated:

    .DEFINE bigapple_h $BFFF
    .DEFINE bigapple_l $BFFE
    .DEFINE bigapple   $BFFE
    .EXPORT bigapple, bigapple_l, bigapple_h

This way you can generate a 16-bit variable address along with pointers to its parts.

Here’s another example with a nameless INSTANCEOF:

    .STRUCT position_t
    pos_x  DW
    pos_y  DW
    .ENDST

    .STRUCT enemy_t
    id     DW
           INSTANCEOF position_t ; here we import fields from position_t
    health DW
    .ENDST

    .ENUM $A000
    nemesis INSTANCEOF enemy_t
    .ENDE

Regarding nemesis, you’ll get these definitions:

    .DEFINE nemesis        $A000
    .DEFINE nemesis.id     $A000
    .DEFINE nemesis.pos_x  $A002
    .DEFINE nemesis.pos_y  $A004
    .DEFINE nemesis.health $A006

If you want more flexible variable positioning, take a look at `.RAMSECTION` s.

You can also specify the size of an instantiated struct (padding added at the end) using the keyword `SIZE`. Also use keyword `COUNT` to make things more clear:

    .STRUCT mon                            ; the size of this .STRUCT is 3 (bytes)
    name ds 2
    age  db
    .ENDST

    .ENUM $A000
    monsters INSTANCEOF mon SIZE 4 COUNT 2 ; two instances of structure mon.
    .ENDE                                  ; each instance is padded to 4 bytes.

Note that in the previous example we’ll also get extra definitions

> _paddingof_monsters.1 (== 1) _paddingof_monsters.2 (== 1)

This is not a compulsory directive.

## 3.88. `.ENUMID ID_1 0`

`.ENUMID` will create definitions with an autoincrementing value. For example:

    .ENUMID 0
    .ENUMID ID_1
    .ENUMID ID_2
    .ENUMID ID_3

… will create the following definitions:

    ID_1 = 0
    ID_2 = 1
    ID_3 = 2

You can also specify the adder:

    .ENUMID 0 STEP 2
    .ENUMID MONSTER_ID_1
    .ENUMID MONSTER_ID_2
    .ENUMID MONSTER_ID_3

… to create definitions:

    MONSTER_ID_1 = 0
    MONSTER_ID_2 = 2
    MONSTER_ID_3 = 4

If you wish to export the definitions automatically, use EXPORT:

    .ENUMID 16 STEP 2 EXPORT
    .ENUMID MUSIC_1
    .ENUMID MUSIC_2
    .ENUMID MUSIC_3

… will create the following definitions and export them all:

    MUSIC_1 = 16
    MUSIC_2 = 18
    MUSIC_3 = 20

This is not a compulsory directive.

## 3.89. `.EQU IF $FF0F`

`.EQU` is an alias for `.DEFINE`.

This is not a compulsory directive.

## 3.90. `.EXHIROM`

With this directive you can define the SNES ROM mode to be ExHiROM. Issuing `.EXHIROM` will override the user’s ROM bank map when WLALINK computes 24-bit addresses and bank references. If no `.HIROM`, `.LOROM` or `.EXHIROM` are given then WLALINK obeys the banking defined in `.ROMBANKMAP`.

`.EXHIROM` also sets the ROM mode bit in `$40FFD5` (mirrored in `$FFD5`).

This is not a compulsory directive.

## 3.91. `.EXPORT work_x`

Exports the definition `work_x` to outside world. Exported definitions are visible to all object files and libraries in the linking procedure. Note that you can only export value definitions, not string definitions.

You can export as many definitions as you wish with one `.EXPORT`:

    .EXPORT NUMBER, NAME, ADDRESS, COUNTRY
    .EXPORT NAME, AGE

This is not a compulsory directive.

## 3.92. `.FAIL "THE EYE OF MORDOR HAS SEEN US!"`

Terminates the compiling process. You can also specify the error code:

    .FAIL 2

These work as well:

    .FAIL
    .FAIL "EXIT CODE IS 1"
    .FAIL "UH ", "OH...", 3

By default, if you don’t specify the error code, it’ll be 1.

This is not a compulsory directive.

## 3.93. `.FARADDR main, irq_1`

`.FARADDR` is an alias for `.DL`.

This is not a compulsory directive.

## 3.94. `.FASTROM`

Sets the ROM memory speed bit in `$FFD5` (`.HIROM`), `$7FD5` (`.LOROM`) or `$FFD5` and `$40FFD5` (`.EXHIROM`) to indicate that the SNES ROM chips are 120ns chips.

This is not a compulsory directive.

## 3.95. `.FCLOSE FP_DATABIN`

Closes the filehandle `FP_DATABIN`.

This is not a compulsory directive.

## 3.96. `.FILTER filtermacro 1, 2, "encrypt me"`

Runs the supplied data, in bytes, through a filter macro. All the data is passed to `filtermacro` in the first argument, one byte at a time. The second macro argument holds the offset from the beginning (the first byte) in bytes (the series being `0`, `1`, `2`, `3`, …).

Here’s an example of a filter macro that defines bits (four per byte):

    .macro increment
    .bits 4 \1
    .endm

Here’s a bigger example where we map some ASCII characters into 4 bits per char:

    // define an array for mapping ASCII values into less bits
    .ARRAYDEFINE NAME MapArray SIZE 4

    .ARRAYIN NAME MapArray INDEX 'A' VALUES %0000, %0001, %0010, \
        %0011, %0100, %0101, %0110 // defines mappings for A-G
    .ARRAYIN NAME MapArray INDEX  0  VALUE %1111

    .MACRO MapInto4Bits
    .ARRAYOUT NAME MapArray INDEX \1 DEFINITION MAPPING
    .BITS 4 MAPPING
    .IF \1 == 0
        .ENDBITS
    .ENDIF
    .ENDM

    .FILTER MapInto4Bits "BAGED", 0

This is not a compulsory directive.

## 3.97. `.FOPEN "data.bin" FP_DATABIN`

Opens the file `data.bin` for reading and associates the filehandle with name `FP_DATABIN`.

This is not a compulsory directive.

## 3.98. `.FREAD FP_DATABIN DATA`

Reads one byte from `FP_DATABIN` and creates a definition called `DATA` to hold it. `DATA` is an ordinary definition label, so you can `.UNDEFINE` it.

Here’s an example on how to use `.FREAD`:

    .fopen "data.bin" fp
    .fsize fp t
    .repeat t
    .fread fp d
    .db d+26
    .endr
    .undefine t, d

This is not a compulsory directive.

## 3.99. `.FSEEK FP_DATABIN 10 START`

Sets the file position of the given file pointer. There are three modes:

    .FSEEK FP_DATABIN 10 START   ; 10 bytes from the beginning of the file
    .FSEEK FP_DATABIN -10 END    ; 10 bytes before the end of the file
    .FSEEK FP_DATABIN 10 CURRENT ; 10 bytes forward from the current
                                 ; position

This is not a compulsory directive.

## 3.100. `.FSIZE FP_DATABIN SIZE`

Creates a definition called `SIZE`, which holds the size of the file associated with the filehandle `FP_DATABIN`. `SIZE` is an ordinary definition label, so you can `.UNDEFINE` it.

This is not a compulsory directive.

## 3.101. `.FTELL FP_DATABIN POSITION`

Creates a definition called `POSITION`, which holds the file position of the file associated with the filehandle `FP_DATABIN`. `POSITION` is an ordinary definition label, so you can `.UNDEFINE` it.

This is not a compulsory directive.

## 3.102. `.FUNCTION SUM_AB(varA,varB)`

Creates a function called `SUM_AB`. Here are some examples:

    .FUNCTION SUM_AB(varA, varB) (varA + varB)
    .FUNCTION SUB_A_6(varA) varA-6
    .FUNCTION SUM_ABC(varA, varB, varC) (SUM_AB(varA, varB) + varC)
    .FUNCTION CONSTANT_1() 1

You can also use `.DEFINE` to create a function by putting `(` immediately after the name:

    .DEFINE ADD_THREE(value) value + 3

`.FUNCTION` can be used anywhere values are expected:

    LDA SUM_AB(1, 2)
    .DEFINE SUM = 0 + 1 + SUM_AB(2, 3) + 4 + 5

This is not a compulsory directive.

## 3.103. `.GBHEADER`

This begins the GB header definition, and automatically defines `.COMPUTEGBCHECKSUM`. End the header definition with .ENDGB. Here’s an example:

    .GBHEADER
        NAME "TANKBOMBPANIC"  ; identical to a freestanding .NAME.
        LICENSEECODEOLD $34   ; identical to a freestanding .LICENSEECODEOLD.
        LICENSEECODENEW "HI"  ; identical to a freestanding .LICENSEECODENEW.
        CARTRIDGETYPE $00     ; identical to a freestanding .CARTRIDGETYPE.
        RAMSIZE $09           ; identical to a freestanding .RAMSIZE.
        ROMSIZE               ; identical to a freestanding .ROMSIZE.
        COUNTRYCODE $01       ; identical to a freestanding .COUNTRYCODE/DESTINATIONCODE.
        DESTINATIONCODE $01   ; identical to a freestanding .DESTINATIONCODE/COUNTRYCODE.
        NINTENDOLOGO          ; identical to a freestanding .NINTENDOLOGO.
        VERSION $01           ; identical to a freestanding .VERSION.
        ROMDMG                ; identical to a freestanding .ROMDMG.
                              ; Alternatively, ROMGBC or ROMGBCONLY can be used
    .ENDGB

This is not a compulsory directive.

## 3.104. `.HEX "a0A0ffDE"`

Defines bytes using the supplied string that contains the bytes in hexadecimal format. For example, the same result can be obtained using `.DB`

    .DB $a0, $A0, $ff, $DE

`.HEX` can also be used in the following ways:

    .HEX 01 AA 02 BB 03 CC    ; -> .DB $01, $AA, $02, $BB, $03, $CC
    .HEX BLOCK
         01 02 03 04 05 06    ; -> .DB $01, $02, $03, $04, $05, $06
         07 08 09 0A 0B 0C    ; -> .DB $07, $08, $09, $0A, $0B, $0C
    .ENDHEX

This is not a compulsory directive.

## 3.105. `.HIROM`

With this directive you can define the SNES ROM mode to be HiROM. Issuing `.HIROM` will override the user’s ROM bank map when WLALINK computes 24-bit addresses and bank references. If no `.HIROM`, `.LOROM` or `.EXHIROM` are given then WLALINK obeys the banking defined in `.ROMBANKMAP`.

`.HIROM` also sets the ROM mode bit in `$FFD5`.

This is not a compulsory directive.

## 3.106. `.INESHEADER`

Defines a 16-byte iNES or NES 2.0 file header for WLA-6502 NES projects. The header is emitted as a bank 0 `BANKHEADER` section, so WLALINK writes it before the first PRG ROM bank. Do not define another `BANKHEADER` section for bank 0 in the same project.

`PRGROMSIZE` is required and is counted in 16KB units. `CHRROMSIZE` is counted in 8KB units and defaults to 0, which is commonly used for CHR RAM. `MAPPER` defaults to 0, and `MIRRORING` accepts `HORIZONTAL` or `VERTICAL`:

    .INESHEADER
        PRGROMSIZE 2
        CHRROMSIZE 1
        MAPPER 4
        MIRRORING VERTICAL
        BATTERY
    .ENDINES

The following iNES flags are recognized: `BATTERY`, `TRAINER`, `FOURSCREEN`, `VS` / `VSUNISYSTEM`, `PLAYCHOICE` / `PLAYCHOICE10`, `PRGRAMSIZE`, `TVSYSTEM` (`NTSC` or `PAL`) and `FLAGS10`.

Use `NES2` inside the block to emit a NES 2.0 header. NES 2.0 adds `SUBMAPPER`, `PRGRAM`, `PRGNVRAM`, `CHRRAM`, `CHRNVRAM`, `CPUPPUTIMING` / `TIMING` (`NTSC`, `PAL`, `DUAL` or `DENDY`), `VSHARDWARE`, `VSPPUTYPE`, `MISCROMS` and `DEFAULTEXPANSIONDEVICE` / `EXPANSIONDEVICE`. The RAM fields are the NES 2.0 shift-count nibbles, not byte counts.

A complete NES 2.0 header using the extended fields could look like this:

    .INESHEADER
        NES2
        PRGROMSIZE 512
        CHRROMSIZE 128
        MAPPER 268
        SUBMAPPER 3
        MIRRORING HORIZONTAL
        BATTERY
        VS
        PRGRAM 7
        PRGNVRAM 8
        CHRRAM 6
        CHRNVRAM 0
        CPUPPUTIMING DUAL
        VSHARDWARE 1
        VSPPUTYPE 3
        MISCROMS 1
        EXPANSIONDEVICE 2
    .ENDINES

This is not a compulsory directive.

## 3.107. `.IF DEBUG == 2`

If the condition is fulfilled the following piece of code is acknowledged until `.ENDIF` / `.ELSE` / `.ELIF` occurs in the text, otherwise it is skipped. Operands must be immediate values or strings.

The following operators are supported:

`!` | not
`<` | less than
`<=` | less or equal to
`>` | greater than
`>=` | greater or equal to
`==` | equals to
`!=` | doesn’t equal to
`||` | logical or
`&&` | logical and

All `IF` directives (yes, including `.IFDEF`, `.IFNDEF`, etc) can be nested. They can also be used within `ENUM` s, `RAMSECTION` s, `STRUCT` s, `ROMBANKMAP` s, and most other directives that occupy multiple lines.

Note that complex conditions are also possible

    .IF DEBUG == 2 && defined(HELLO) && exists("main.s")

Here defined() and exists() both return 1 of they are true, and 0 if false. In fact in conditions 0 is false and anything else is considered to be true.

This is not a compulsory directive.

## 3.108. `.IFDEF IF`

If `IF` is defined, then the following piece of code is acknowledged until `.ENDIF` / `.ELSE` occurs in the text, otherwise it is skipped.

This is not a compulsory directive.

## 3.109. `.IFDEFM \2`

If the specified argument is defined (argument number two, in the example), then the following piece of code is acknowledged until `.ENDIF` / `.ELSE` occurs in the macro, otherwise it is skipped.

This is not a compulsory directive. `.IFDEFM` works only inside a macro.

## 3.110. `.IFEQ DEBUG 2`

If the value of `DEBUG` equals to `2`, then the following piece of code is acknowledged until `.ENDIF` / `.ELSE` occurs in the text, otherwise it is skipped. Both arguments can be computations, defines or immediate values.

This is not a compulsory directive.

## 3.111. `.IFEXISTS "main.s"`

If `main.s` file can be found, then the following piece of code is acknowledged until `.ENDIF` / `.ELSE` occurs in the text, otherwise it is skipped.

By writing the following few lines you can include a file if it exists without breaking the compiling loop if it doesn’t exist:

    .IFEXISTS FILE
    .INCLUDE FILE
    .ENDIF

This is not a compulsory directive.

## 3.112. `.IFGR DEBUG 2`

If the value of `DEBUG` is greater than `2`, then the following piece of code is acknowledged until `.ENDIF` / `.ELSE` occurs in the text, otherwise it is skipped. Both arguments can be computations, defines or immediate values.

This is not a compulsory directive.

## 3.113. `.IFGREQ DEBUG 2`

If the value of `DEBUG` is greater or equal to `2`, then the following pieceof code is acknowledged until `.ENDIF` / `.ELSE` occurs in the text, otherwise it is skipped. Both arguments can be computations, defines or immediate values.

This is not a compulsory directive.

## 3.114. `.IFLE DEBUG 2`

If the value of `DEBUG` is less than `2`, then the following piece of code is acknowledged until `.ENDIF` / `.ELSE` occurs in the text, otherwise it is skipped. Both arguments can be computations, defines or immediate values.

This is not a compulsory directive.

## 3.115. `.IFLEEQ DEBUG 2`

If the value of `DEBUG` is less or equal to `2`, then the following piece of code is acknowledged until `.ENDIF` / `.ELSE` occurs in the text, otherwise it is skipped. Both arguments can be computations, defines or immediate values.

This is not a compulsory directive.

## 3.116. `.IFNDEF IF`

If `IF` is not defined, then the following piece of code is acknowledged until `.ENDIF` / `.ELSE` occurs in the text, otherwise it is skipped.

This is not a compulsory directive.

## 3.117. `.IFNDEFM \2`

If the specified argument is not defined, then the following piece of code is acknowledged until `.ENDIF` / `.ELSE` occurs in the macro, otherwise it is skipped.

This is not a compulsory directive. `.IFNDEFM` works only inside a macro.

## 3.118. `.IFNEQ DEBUG 2`

If the value of `DEBUG` doesn’t equal to `2`, then the following piece of code is acknowledged until `.ENDIF` / `.ELSE` occurs in the text, otherwise it is skipped. Both arguments can be computations, defines or immediate values.

This is not a compulsory directive.

## 3.119. `.INC "cgb_hardware.i"`

`INC` is an alias for `INCLUDE`.

This is not a compulsory directive.

## 3.120. `.INCBIN "sorority.bin"`

Includes the specified data file into the source file. `.INCBIN` caches all files into memory, so you can `.INCBIN` any data file millions of times, but it is loaded from hard drive only once.

You can optionally use `SWAP` after the file name, e.g.,

    .INCBIN "kitten.bin" SWAP

`.INCBIN` data is divided into blocks of two bytes, and inside every block the bytes are exchanged (like `SWAP r` does to nibbles). This requires that the size of the read data is even.

You can also force WLA to skip n bytes from the beginning of the file by writing for example:

    .INCBIN "kitten.bin" SKIP 4

Four bytes are skipped from the beginning of `kitten.bin` and the rest is incbinned.

It is also possible to incbin only n bytes from a file:

    .INCBIN "kitten.bin" READ 10 FREADSIZE bytesRead

Will read ten bytes from the beginning of `kitten.bin` and create a definition called `bytesRead` with value 10. If you make `READ` negative, like:

    .INCBIN "kitten.bin" READ -2

all bytes except the last two are read. To extend this:

    .INCBIN "kitten.bin" SKIP 1 READ -2

and one byte will be skipped at the beginning of the file and two at the end.

You can also force WLA to create a definition holding the size of the file:

    .INCBIN "kitten.bin" FSIZE size_of_kitten

Want to circulate all the included bytes through a filter macro? Do this:

    .INCBIN "kitten.bin" FILTER filtermacro

The filter macro is executed for each byte of the included data, data byte being the first argument, and offset from the beginning being the second parameter, just like in the case of `.DBM`, `.DWM`, `.DLM` and `.DDM`.

And you can combine all these four commands:

    .INCBIN "kitten.bin" SKIP 10 READ 8 SWAP FSIZE size_of_kitten FILTER filtermacro

This example shows how to incbin eight bytes (swapped) after skipping 10 bytes from the beginning of file `kitten.bin`, and how to get the size of the file into a definition label `size_of_kitten`. All the data bytes are circulated through a filter macro.

Here’s an example of a filter macro that increments all the bytes by one:

    .macro filtermacro    ; the input byte is \1, the output byte is in "_out"
    .redefine _out \1+1   ; \2 is the index of the element
    .endm

Instead of passing just one byte at a time to the filter macro, you can specify the chunk size as follows:

    .INCBIN "kitten.bin" FILTER filtermacro FILTERSIZE 4

`FILTERSIZE` specifies the chunk size of the number of bytes (read) in 1 in the filter macro. 2 in the macro specifies the index of the chunk and 3 specifies the size of the chunk (same as `FILTERSIZE`). You can still use `SWAP` to change the order of the bytes in 1.

If the file’s not found in the `.INCDIR` directory, WLA tries to find it in the current working directory. If the `INCDIR` is specified in the command line, WLA will first search for the file in that directory. If not found, it will then proceed as aforementioned.

To use the latest directory we’ve used to `.INCLUDE` or `.INCBIN` a file, issue `LATESTDIR`:

    .INCBIN "rgb.bin" LATESTDIR

To use the current file’s directory, issue `RELATIVEDIR`:

    .INCBIN "rgb.bin" RELATIVEDIR

This is not a compulsory directive.

## 3.121. `.INCDIR "/usr/programming/gb/include/"`

Changes the current include root directory. Use this to specify main directory for the following `.INCLUDE`, `.INCBIN` and `.STRINGMAPTABLE` directives. If you want to change to the current working directory (WLA also defaults to this), use:

    .INCDIR ""

If the `INCDIR` is specified in the command line, that directory will be searched before the `.INCDIR` in the file. If the file is not found, WLA will then silently search the specified `.INCDIR`.

This is not a compulsory directive.

## 3.122. `.INCLUDE "cgb_hardware.i"`

Includes the specified file to the source file. If the file’s not found in the `.INCDIR` directory, WLA tries to find it in the current working directory. If the `INCDIR` is specified in the command line, WLA will first try to find the file specified in that directory. Then proceed as mentioned before if it is not found.

If you want to prefix all labels inside the included file with something, use:

    .INCLUDE "music_player.s" NAMESPACE "musicplayer"

In the case of this example, all sections, macros, labels and references to those labels inside the included file are prefixed with “musicplayer.”, though there are a couple of exceptions. If a `.SECTION` inside the included file has its own namespace, the `.INCLUDE` ‘s namespace doesn’t affect it. If a `.SECTION` inside the included file uses `APPENDTO` with a section name that starts with `"*:"`, that `APPENDTO` is considered to belong to the global namespace and we won’t prefix it with the `.INCLUDE` ‘s namespace.

To add the namespace prefix to everything including `.DEFINE` s use the keyword `ISOLATED`:

    .INCLUDE "music_player.s" NAMESPACE "musicplayer" ISOLATED

Note that a dot is the namespace separator so your namespace cannot contain a dot.

Note that you can create the file name from pieces:

    .INCLUDE ROOTDIR, SUBDIR, "cthulhu.s" NAMESPACE "cthulhu"

This might end up looking for a file “root/subdir/cthulhu.s”, depending on the definitions.

If you are using the `.INCLUDE` inside a `.MACRO` and want to have the file included only once, use the keyword `ONCE`:

    .INCLUDE "include_one.s" NAMESPACE "once" ONCE

To use the latest directory we’ve used to `.INCLUDE` or `.INCBIN` a file, issue `LATESTDIR`:

    .INCLUDE "common.i" LATESTDIR

To use the current file’s directory, issue `RELATIVEDIR`:

    .INCLUDE "common.i" RELATIVEDIR

This is not a compulsory directive.

## 3.123. `.INDEX 8`

Forces WLA to override the index (`X` / `Y`) register size given with `SEP` / `REP`. `.INDEX` doesn’t produce any code, it only affects the way WLA interprets the immediate values (`8` for 8 bit operands, `16` for 16 bit operands) for opcodes dealing with the index registers.

So after giving `.INDEX 8`

> CPX #10

will produce `$E0 $A0`, and after giving `.INDEX 16`

> CPX #10

will yield `$E0 $00 $A0`.

Note that `SEP` / `REP` again will in turn reset the accumulator/index register size.

This is not a compulsory directive.

## 3.124. `.INPUT NAME`

`.INPUT` is much like any Basic-language input: `.INPUT` asks the user for a value or string. After `.INPUT` is the variable name used to store the data.

`.INPUT` works like `.REDEFINE`, but the user gets to type in the data.

Here are few examples how to use input:

    .PRINTT "The name of the ROM? "
    .INPUT NAME
    .NAME NAME

    ...

    .PRINTT "Give the .DB amount.\n"
    .INPUT S
    .PRINTT "Give .DB data one at a time.\n"
    .REPEAT S
      .INPUT B
      .DB B
    .ENDR

    ...

This is not a compulsory directive.

## 3.125. `.LICENSEECODENEW "1A"`

This is a standard new licensee code found at `$144` and `$145` in a Gameboy ROM, and there this one is put to also. `.LICENSEECODENEW` cannot be defined with .LICENSEECODEOLD. `$33` is inserted into `$14B`, as well.

This is not a compulsory directive.

## 3.126. `.LICENSEECODEOLD $1A`

This is a standard old licensee code found at `$14B` in a Gameboy ROM, and there this one is put to also. `.LICENSEECODEOLD` cannot be defined with `.LICENSEECODENEW`.

This is not a compulsory directive.

## 3.127. `.LONG $102030, $405060`

`.LONG` is an alias for `.DL`.

This is not a compulsory directive.

## 3.128. `.LOROM`

With this directive you can define the SNES ROM mode to be LoROM. Issuing `.LOROM` will override the user’s ROM bank map when WLALINK computes 24-bit addresses and bank references. If no `.HIROM`, `.LOROM` or `.EXHIROM` are given then WLALINK obeys the banking defined in `.ROMBANKMAP`.

WLA defaults to `.LOROM`.

This is not a compulsory directive.

## 3.129. `.LYNXHEADER`

Defines a 64-byte Atari Lynx `.lnx` file header for WLA-65C02 projects. The header is emitted as a bank 0 `BANKHEADER` section, so WLALINK writes it before the first cartridge ROM bank. Do not define another `BANKHEADER` section for bank 0 in the same project.

`BANK0BLOCKSIZE` is required. `BANK1BLOCKSIZE` defaults to 0. These values are the Lynx header page/block sizes, not byte counts: `$100` means 64KB, `$200` means 128KB, `$400` means 256KB, `$800` means 512KB and `$1000` means 1024KB. `BANK1BLOCKSIZE` also accepts 0 for no second bank. `VERSION` defaults to 1, the standard `.lnx` version.

`NAME` / `CARTNAME` accepts up to 31 characters and `MANUFACTURER` / `MANUFACTURERNAME` accepts up to 15 characters. Both are stored as padded C strings in the fixed-size header fields. `ROTATION` accepts `NONE`, `LEFT` or `RIGHT`. `AUDIN` accepts `OFF` or `ON`. `EEPROM` accepts `NONE`, `93C46`, `93C56`, `93C66`, `93C76` or `93C86`; the `_8BIT` and `_16BIT` suffixes can be added to those EEPROM names. Use `EEPROMVALUE` to write a raw EEPROM byte, `EEPROM8BIT` / `EEPROM16BIT` to adjust the access-width flag, and `EEPROMSD` to set the SD flag. `SPARE` writes the three spare bytes:

    .LYNXHEADER
        BANK0BLOCKSIZE $400
        BANK1BLOCKSIZE 0
        NAME "HELLO LYNX"
        MANUFACTURER "WLA DX"
        ROTATION NONE
        AUDIN OFF
        EEPROM NONE
    .ENDLYNX

This is not a compulsory directive.

## 3.130. `.MACRO TEST`

Begins a macro called `TEST`.

You can use `\@` inside a macro to e.g., separate a label from the other macro `TEST` occurrences. `\@` is replaced with an integer number indicating the amount of times the macro has been called previously so it is unique to every macro call. `\@` can also be used inside strings inside a macro or just as a plain value. Look at the following examples for more information.

You can also type `\!` to get the name of the source file currently being parsed. `\.` can be used the same way to get the name of the macro.

Also, if you want to use macro arguments in e.g., calculation, you can type `\X` where `X` is the number of the argument. Another way to refer to the arguments is to use their names given in the definition of the macro (see the examples for this).

Remember to use `.ENDM` to finish the macro definition. Note that you cannot use `.INCLUDE` inside a macro. Note that WLA’s macros are in fact more like procedures than real macros, because WLA doesn’t substitute macro calls with macro data. Instead WLA jumps to the macro when it encounters a macro call at compile time.

You can call macros from inside a macro. Note that the preprocessor does not expand the macros. WLA traverses through the code according to the macro calls.

Here are some examples:

    .MACRO NOPMONSTER
        .REPT 32         ; gives us 32 NOPs
        NOP
        .ENDR
    .ENDM

    .MACRO LOAD_ABCD
        LD A, \1
        LD B, \2
        LD C, \3
        LD D, :\4        ; load the bank number of \4 into register D.
        NOPMONSTER       ; note that \4 must be a label or ROM address
        LD HL, 1<<\1     ; for this to work...
    .INCBIN \5
    .ENDM

    .MACRO QUEEN

    QUEEN\@:
        LD   A, \1
        LD   B, \1
        CALL QUEEN\@

        .DB  "\@", 0     ; will translate into a zero terminated string
                         ; holding the amount of macro QUEEN calls.
        .DB  "\\@", 0    ; will translate into a string containing
                         ; \@.
        .DB  \@          ; will translate into a number indicating
                         ; the amount of macro QUEEN calls.

    .ENDM

    .MACRO LOAD_ABCD_2 ARGS ONE, TWO, THREE, FOUR, FIVE
        LD A, ONE        ; note! ONE, TWO, THREE, FOUR and FIVE
        LD B, TWO        ; here are actually definitions that
        LD C, THREE      ; exist as long as the .MACRO is alive
        LD D, FOUR       ; so be careful when using named args...
        NOPMONSTER
        LD HL, 1<<ONE
    .INCBIN FIVE
    .ENDM

And here’s how they can be used:

    NOPMONSTER
    LOAD_ABCD $10, $20, $30, XYZ, "merman.bin"
    QUEEN 123
    LOAD_ABCD_2 $10, $20, $30, XYZ, "merman.bin"

Note that arguments can be optionally wrapped inside parentheses:

    NOPMONSTER()
    LOAD_ABCD($10, $20, $30, XYZ, "merman.bin")
    QUEEN(123)
    LOAD_ABCD_2($10, $20, $30, XYZ, "merman.bin")

Note that you must separate the arguments with commas.

Note that the following works as well:

    .DEF prev_test $0000

    .MACRO test ARGS str
    __\._{\@+1}:                   ; this will become __test_1 during
        .PRINT __\._{\@+1}, "\n"   ; the first call, __test_2 during the
        .WORD  prev_test           ; second call...
        .REDEF prev_test __\._{\@+1}
        .BYTE  str.length, str, 0
    .ENDM

If you want to give names to the macro’s arguments you can do that by listing them in order after supplying ARGS after the macro’s name.

Every time a macro is called a definition `NARGS` is created. It shows only inside the macro and holds the number of arguments the macro was called with. So don’t have your own definition called `NARGS`. Here’s an example:

    .MACRO LUPIN
      .IF NARGS != 1
        .FAIL
      .ENDIF

      .PRINTT "Totsan! Ogenki ka?\n"
    .ENDM

You can also use `\?` to ask for the type of the argument in the following fashion:

    .macro differentThings
      .if \?1 == ARG_IMMEDIATE
        .db \1
      .elif \?1 == ARG_NUMBER
        .db 1
      .elif \?1 == ARG_STRING
        .db 2
      .elif \?1 == ARG_LABEL
        .db 3
      .elif \?1 == ARG_PENDING_CALCULATION
        .db 4
      .endif
    .endm

    .section "TestingDifferentThings"
    TDT1:
        differentThings 100
        differentThings "HELLO"
        differentThings TDT1
        differentThings TDT1+1
        differentThings #0
    .ends

The previous example will result in .db 1, 2, 3, 4, 0

Here’s another useful example:

    .DEFINE DEFINITION_A 1

    .MACRO REDEFINER
    .REDEFINE \1 = ?1 + 1      ; \1 here is the definition's name,
    .ENDM                      ; and ?1 is its value.

    REDEFINER &DEFINITION_A    ; here we feed the definition's name
                               ; as first argument, not it's value

Another useful example:

    .MACRO LOOP ISOLATED
       LD A, 10
    -  DEC A                   ; B
       JP NZ, -
    .ENDM

    ...
       LD B, 20
    -  LOOP                    ; C
       DEC B
       JP NZ, -                ; A
    ...

Here we use the keyword `ISOLATED` to make un-named labels inside the macro to be isolated from the outside world. Without it the jump in A would jump to B, but now it jumps to C.

Using the keyword `ISOLATED` we would also make the macro to have its own child label stack:

            .macro MACROM
    AA03:   .db 0
    @child: .db 1          ; A
            .dw @child     ; B
            .endm

    AA00:   .db "25>"
    @child: MACROM         ; C
            .dw @child     ; D
            .db "<25"

In this case B points to A and D points to A. If you add keyword `ISOLATED` to `.MACRO` MACROM then B still points to A, but A doesn’t leak out of MACROM and D points to C. Exiting a `.MACRO` that uses keyword `ISOLATED` restores the child label stack.

One example more, but this time with local labels:

            .macro LOCALS isolated
    _hello: .db 0            ; A
            .dw _hello + 1   ; B
            .endm

    _hello: .db "27>"        ; C
            .db 0, 1, 2
            LOCALS
            .dw _hello + 2   ; D
            .db "<27"

Normally this would create the local label `_hello` twice and it would not work. Adding the keyword `ISOLATED` to `.MACRO` makes the local labels unique and D points to C and B points to A.

To enable only local label isolation use the keyword `ISOLATELOCAL` instead of `ISOLATED` and to enable only the isolation of un-named labels use the keyword `ISOLATEUNNAMED`.

Note that there is an alternative way of defining a `.MACRO`:

    .macro DBSUMOFTWOVALUES(v1,v2) isolated
      .db v1+v2
    .endm

To let the `.MACRO` create child labels to the latest label defined before the `.MACRO` is called, use `CHILDLABELS`:

           .macro extras childlabels
    child: nop
    @granchild:
           jp ?@granchild
           .endm

    parent:
           extras

The example will create labels `parent`, `parent@child` and `parent@child@granchild`. Note that if you want to reference these labels inside the `.MACRO` you’ll need to prefix the labels with a `?`.

This is not a compulsory directive.

## 3.131. `.MEMORYMAP`

Begins the memory map definition. Using `.MEMORYMAP` you must first describe the target system’s memory architecture to WLA before it can start to compile the code. `.MEMORYMAP` gives you the freedom to use WLA to compile data for numerous different real systems.

Examples:

    .MEMORYMAP
    DEFAULTSLOT 0
    SLOTSIZE $4000
    SLOT 0 $0000
    SLOT 1 $4000
    .ENDME

    .MEMORYMAP
    DEFAULTSLOT 0
    SLOT 0 $0000 $4000 "ROMSlot"
    SLOT 1 $4000 $4000 "RAMSlot"
    .ENDME

    .MEMORYMAP
    DEFAULTSLOT 0
    SLOT 0 START $0000 SIZE $4000 NAME "ROMSlot"
    SLOT 1 START $4000 SIZE $4000 NAME "RAMSlot"
    .ENDME

    .MEMORYMAP
    DEFAULTSLOT 1
    DEFAULTSECTIONSLOT 1
    DEFAULTRAMSECTIONSLOT 2
    SLOTSIZE $6000
    SLOT 0 $0000
    SLOTSIZE $2000
    SLOT 1 $6000
    SLOT 2 $8000
    .ENDME

Here’s a real life example from Adam Klotblixt. It should be interesting for all the ZX81 coders:

    ...

    .MEMORYMAP
    DEFAULTSLOT 1
    SLOTSIZE $2000
    SLOT 0 $0000
    SLOTSIZE $6000
    SLOT 1 $2000
    .ENDME

    .ROMBANKMAP
    BANKSTOTAL 2
    BANKSIZE $2000
    BANKS 1
    BANKSIZE $6000
    BANKS 1
    .ENDRO

    .BANK 1 SLOT 1
    .ORGA $2000

    ...

`SLOTSIZE` defines the size of the following slots, unless you explicitly specify the size of the slot, like in the second and third examples. You can redefine `SLOTSIZE` as many times as you wish.

`DEFAULTSLOT` describes the default slot for banks which aren’t explicitly inserted anywhere. Check `.BANK` definition for more information.

`DEFAULTSECTIONSLOT` describes the default slot for a `.SECTION`.

`DEFAULTRAMSECTIONSLOT` describes the default slot for a `.RAMSECTION`.

`SLOT` defines a slot and its starting address. `SLOT` numbering starts at `0` and ends to `255` so you have 256 slots at your disposal.

This is a compulsory directive, and make sure all the object files share the same `.MEMORYMAP` or you can’t link them together.

## 3.132. `.NAME "NAME OF THE ROM"`

If `.NAME` is used with WLA-GB then the 16 bytes ranging from `$0134` to `$0143` are filled with the provided string. WLA-65816 fills the 21 bytes from `$FFC0` to `$FFD4` in HiROM and from `$7FC0` to `$7FD4` in LoROM mode with the name string (SNES ROM title). For ExHiROM the ranges are from `$40FFC0` to `$40FFD4` and from `$FFC0` to `$FFD4` (mirrored).

If the string is shorter than 16/21 bytes the remaining space is filled with `$00`.

This is not a compulsory directive.

## 3.133. `.NEXTU name`

Proceeds to the next entry in a union.

## 3.134. `.NINTENDOLOGO`

Places the required Nintendo logo into the Gameboy ROM at `$104`.

This is not a compulsory directive.

## 3.135. `.NOWDC`

Turns WLA-65816 into a mode where it accepts its default syntax assembly code, which doesn’t support WDC standard. This is the default mode for WLA-65816.

This is not a compulsory directive.

## 3.136. `.ORG $150`

Defines the starting address. The value supplied here is relative to the ROM bank given with `.BANK`.

When WLA starts to parse a source file, `.ORG` is set to `$0`, but it’s always a good idea to explicitly use `.ORG`, for clarity.

This is a compulsory directive.

## 3.137. `.ORGA $150`

Defines the starting address. The value supplied here is absolute and used directly in address computations. WLA computes the right position in ROM file. By using `.ORGA` you can instantly see from the source file where the following code is located in the 16-bit memory.

Here’s an example:

    .MEMORYMAP
    SLOTSIZE $4000
    DEFAULTSLOT 0
    SLOT 0 $0000
    SLOT 1 $4000
    .ENDME

    .ROMBANKMAP
    BANKSTOTAL 2
    BANKSIZE $4000
    BANKS 2
    .ENDRO

    .BANK 0 SLOT 1
    .ORGA $4000

    MAIN:       JP      MAIN

Here `MAIN` is at `$0000` in the ROM file, but the address for label `MAIN` is `$4000`. By using `.ORGA` instead of `.ORG`, you can directly see from the value the address where you want the code to be as `.ORG` is just an offset to the `SLOT`.

## 3.138. `.OUTNAME "other.o"`

Changes the name of the output file. Here’s an example:

    wla-gb -o test.o test.s

would normally output `test.o`, but if you had written:

    .OUTNAME "new.o"

somewhere in the code WLA would write the output to `new.o` instead.

This is not a compulsory directive.

## 3.139. `.PRINT "Numbers 1 and 10: ", DEC 1, " $", HEX 10, "\n"`

Prints strings and numbers to stdout. A combination and a more usable version of .PRINTT and .PRINTV. Useful for debugging.

Optional: Give `DEC` (decimal) or `HEX` (hexadecimal) before the value you want to print.

This is not a compulsory directive.

## 3.140. `.PRINTT "Here we are...\n"`

Prints the given text into stdout. Good for debugging stuff. `PRINTT` takes only a string as argument, and the only supported formatting symbol is `\n` (line feed).

This is not a compulsory directive.

## 3.141. `.PRINTV DEC DEBUG+1`

Prints the value of the supplied definition or computation into stdout. Computation must be solvable at the time of printing (just like definitions values). `PRINTV` takes max two parameters. The first describes the type of the print output. `DEC` means decimal, `HEX` means hexadecimal. This is optional. Default is `DEC`.

Use `PRINTV` with `PRINTT` as `PRINTV` doesn’t print linefeeds, only the result. Here’s an example:

    .PRINTT "Value of \"DEBUG\" = $"
    .PRINTV HEX DEBUG
    .PRINTT "\n"

This is not a compulsory directive.

## 3.142. `.RAMSECTION "Vars" BASE $7E BANK 0 SLOT 1 ALIGN 256 OFFSET 32`

`RAMSECTION` s accept only variable labels and variable sizes, and the syntax to define these is identical to `.ENUM` (all the syntax rules that apply to `.ENUM` apply also to `.RAMSECTION`). Additionally you can embed structures (`.STRUCT`) into a `RAMSECTION`. Here’s an example:

    .RAMSECTION "Some of my variables" BANK 0 SLOT 1 RETURNORG PRIORITY 100
    vbi_counter:   db
    player_lives:  db
    .ENDS

By default `RAMSECTION` s behave like `FREE` sections, but instead of filling any banks RAM sections will occupy RAM banks inside slots. You can fill different slots with different variable labels. It’s recommend that you create separate slots for holding variables (as ROM and RAM don’t usually overlap).

If you want that WLA returns the `ORG` to what it was before issuing the `RAMSECTION`, use the keyword `RETURNORG`.

Keyword `PRIORITY` means just the same as `PRIORITY` of a `.SECTION`, it is used to prioritize some sections when placing them in the output ROM/PRG. The `RAMSECTION` s with higher `PRIORITY` are placed first in the output, and if the priorities match, then bigger `RAMSECTION` s are placed first.

NOTE! Currently WLA-DX assumes that there are 256 RAM banks available for each slot in the memory map. There is no other way to limit this number at the moment than manually keep the `BANK` number inside real limits.

Anyway, here’s another example:

    .MEMORYMAP
    SLOTSIZE $4000
    DEFAULTSLOT 0
    SLOT 0 $0000           ; ROM slot 0.
    SLOT 1 $4000           ; ROM slot 1.
    SLOT 2 $A000 "RAMSlot" ; variable RAM is here!
    .ENDME

    .STRUCT game_object
    x DB
    y DB
    .ENDST

    .RAMSECTION "vars 1" BANK 0 SLOT 2
    moomin1   DW
    phantom   DB
    nyanko    DB
    enemy     INSTANCEOF game_object
    .ENDS

    .RAMSECTION "vars 2" BANK 1 SLOT "RAMSlot"  ; Here we use slot 2
    moomin2   DW
    .ENDS

    .RAMSECTION "vars 3" BANK 1 SLOT $A000      ; Slot 2 here as well...
    moomin3_all .DSB 3
    moomin3_a    DB
    moomin3_b    DB
    moomin3_c    DB
    .ENDS

    .RAMSECTION "vars 4" BANK 1 SLOT $A000
    enemies      INSTANCEOF game_object 2 STARTFROM 0 ; If you leave away "STARTFROM 0" the indexing will start from 1
    .ENDS

If no other RAM sections are used, then this is what you will get:

    .DEFINE moomin1     $A000
    .DEFINE phantom     $A002
    .DEFINE nyanko      $A003
    .DEFINE enemy       $A004
    .DEFINE enemy.x     $A004
    .DEFINE enemy.y     $A005
    .DEFINE moomin2     $A000
    .DEFINE moomin3_all $A002
    .DEFINE moomin3_a   $A002
    .DEFINE moomin3_b   $A003
    .DEFINE moomin3_c   $A004
    .DEFINE enemies     $A005
    .DEFINE enemies.0   $A005
    .DEFINE enemies.0.x $A005
    .DEFINE enemies.0.y $A006
    .DEFINE enemies.1   $A007
    .DEFINE enemies.1.x $A007
    .DEFINE enemies.1.y $A008

`BANK` in `.RAMSECTION` is optional so you can leave it away if you don’t switch RAM banks, or the target doesn’t have them (defaults to 0).

NOTE! The generated _sizeof_ labels for `.RAMSECTION` “vars 3” will be:

    _sizeof_moomin3_all (== 3)
    _sizeof_moomin3_a   (== 1)
    _sizeof_moomin3_b   (== 1)
    _sizeof_moomin3_c   (== 1)

Going back to the previous example, if you wanted to make the size of all instances of `game_object` to be 8 (bytes) in `enemies`:

    .RAMSECTION "vars 4" BANK 1 SLOT $A000
    enemies      INSTANCEOF game_object SIZE 8 COUNT 2 STARTFROM 0
    .ENDS

Use the keyword `SIZE` to do that. Also note that the keyword `COUNT` is optional, and recommended.

It is also possible to merge two or more sections using `APPENDTO`:

    .RAMSECTION "RAMSection1" BANK 0 SLOT 0
    label1    DB
    .ENDS

    .RAMSECTION "RAMSection2" APPENDTO "RAMSection1"
    label2    DB
    .ENDS

NOTE! The `APPENDTO` `.SECTION` s are appended in the order the linker sorts them. So first `PRIORITY` is considered (0 by default, the bigger the value the more important it is) and then the size of the `.SECTION` is considered, bigger `.SECTION` s are more important than smaller.

If you wist to skip some bytes without giving them labels, use `.` as a label:

    .RAMSECTION "ZERO_PAGE" BANK 0 SLOT 0
    UsingThisByte1: DB
    .               DB ; RESERVED
    .               DB ; RESERVED
    UsingThisByte2: DB
    .               DB ; RESERVED
    UsingThisByte3: DB
    .ENDS

If you want to use `FORCE` RAMSECTIONs that are fixed to a specified address, do as follows:

    .RAMSECTION "FixedRAMSection" BANK 0 SLOT 0 ORGA $0 FORCE
    .               DB ; SYSTEM RESERVED
    .               DB ; SYSTEM RESERVED
    PlayerX         DB
    PlayerY         DB
    .ENDS

Other types that are supported: `SEMIFREE` and `SEMISUBFREE`.

Note that `.ALIGN` also works inside a `.RAMSECTION`, but there are limitations (see `.ALIGN`). Here’s an example:

    .RAMSECTION "AlignTest" BANK 0 SLOT 1 ALIGN 8
    Objects INSTANCEOF game_object COUNT 2
    .ALIGN 8
    Byte1 DB
    Byte2 DB
    .ALIGN 4
    Checksum DW
    .ENDS

Here’s the order in which WLA writes the RAM sections:

1. `FORCE`

2. `SEMISUBFREE`

3. `SEMIFREE`

4. `FREE`

You can change this order using `[ramsectionwriteorder]` in a link file.

NOTE: You can use `ORGA` to specify the fixed address for a `FORCE` `RAMSECTION`. `ORG` is also supported.

NOTE: When you have `RAMSECTION` s inside libraries, you must give them BANKs and SLOTs in the linkfile, under [ramsections].

NOTE: `WINDOW` and `BITWINDOW` work also with `.RAMSECTION` s.

This is not a compulsory directive.

## 3.143. `.RAMSIZE 0`

Indicates the size of the RAM. This is a standard Gameboy RAM size indicator value found at `$149` in a Gameboy ROM, and there this one is put to also.

This is not a compulsory directive.

## 3.144. `.REDEF IF $0F`

`.REDEF` is an alias for `.REDEFINE`.

This is not a compulsory directive.

## 3.145. `.REDEFINE IF $0F`

Assigns a new value or a string to an old definition. If the definition doesn’t exist, `.REDEFINE` performs `.DEFINE`’s work.

When used with `.REPT` `REDEFINE` helps creating tables:

    .DEFINE CNT 0

    .REPT 256
    .DB CNT
    .REDEFINE CNT CNT+1
    .ENDR

This is not a compulsory directive.

## 3.146. `.REPEAT 6`

Repeats the text enclosed between `.REPEAT x` and `.ENDR` `x` times (`6` in this example). You can use `.REPEAT` s inside `.REPEAT` s. `x` must be bigger or equal than `0`.

It’s also possible to have the repeat counter/index in a definition:

    .REPEAT 6 INDEX COUNT
    .DB COUNT
    .ENDR

This would define bytes `0`, `1`, `2`, `3`, `4` and `5`.

To adjust the initial value and step, use:

    .REPEAT 10 START 100 STEP -10 INDEX COUNT
    .DB COUNT    ; -> 100, 90, 80, 70, 60, 50, 40, 30, 20, 10
    .ENDR

This is not a compulsory directive.

## 3.147. `.REPT 6`

`.REPT` is an alias for `.REPEAT`.

This is not a compulsory directive.

## 3.148. `.ROMBANKMAP`

Begins the ROM bank map definition. You can use this directive to define the project’s ROM banks. Use `.ROMBANKMAP` when not all the ROM banks are of equal size. Note that you can use `.ROMBANKSIZE` and `.ROMBANKS` instead of `.ROMBANKMAP`, but that’s only when the ROM banks are equal in size.

Examples:

    .ROMBANKMAP
    BANKSTOTAL 16
    BANKSIZE $4000
    BANKS 16
    .ENDRO

    .ROMBANKMAP
    BANKSTOTAL 510
    BANKSIZE $6000
    BANKS 1
    BANKSIZE $2000
    BANKS 509
    .ENDRO

The first one describes an ordinary ROM image of 16 equal sized banks. The second one defines a 4MB Pocket Voice ROM image. In the PV ROM image the first bank is `$6000` bytes and the remaining `509` banks are smaller ones, `$2000` bytes each.

`BANKSTOTAL` tells the total amount of ROM banks. It must be defined prior to anything else.

`BANKSIZE` tells the size of the following ROM banks. You can supply WLA with `BANKSIZE` as many times as you wish.

`BANKS` tells the amount of banks that follow and that are of the size `BANKSIZE` which has been previously defined.

This is not a compulsory directive when `.ROMBANKSIZE` and `.ROMBANKS` are defined.

You can redefine `.ROMBANKMAP` as many times as you wish as long as the old and the new ROM bank maps match as much as possible. This way you can enlarge the size of the project on the fly.

## 3.149. `.ROMBANKS 2`

Indicates the size of the ROM in rombanks.

This is a compulsory directive unless `.ROMBANKMAP` is defined.

You can redefine `.ROMBANKS` as many times as you wish as long as the old and the new ROM bank maps match as much as possible. This way you can enlarge the size of the project on the fly.

## 3.150. `.ROMBANKSIZE $4000`

Defines the ROM bank size. Old syntax is `.BANKSIZE x`.

This is a compulsory directive unless `.ROMBANKMAP` is defined.

## 3.151. `.ROMDMG`

Inserts data into the specific ROM location to mark the ROM as a DMG (Gameboy) ROM (`$00` -> `$0146`). It will only run in DMG mode.

This is not a compulsory directive. `.ROMDMG` cannot be used with `.ROMSGB`.

## 3.152. `.ROMGBCONLY`

Inserts data into the specific ROM location to mark the ROM as a Gameboy Color ROM (`$C0` -> `$0143`, so ROM name is max. 15 characters long). It will only run in GBC mode.

This is not a compulsory directive.

## 3.153. `.ROMGBC`

Inserts data into the specific ROM location to mark the ROM as a dual-mode ROM (`$80` -> `$0143`, so ROM name is max. 15 characters long). It will run in either DMG or GBC mode.

This is not a compulsory directive.

## 3.154. `.ROMSGB`

Inserts data into the specific ROM location to mark the ROM as a Super Gameboy enhanced ROM (`$03` -> `$0146`).

This is not a compulsory directive. `.ROMSGB` cannot be used with `.ROMDMG`.

## 3.155. `.ROMSIZE 1`

This is a standard Gameboy ROM size indicator value found at `$148` in a Gameboy ROM, and there this one is put to also. If you don’t specify a value then WLA-GB tries to calculate it based on `.ROMBANKS` / `.ROMBANKMAP`.

This is not a compulsory directive.

## 3.156. `.ROW $ff00, 1, "3"`

Defines bytes after a .TABLE has been used to define the format. An alternative way of defining bytes to .DB/.DW.

Note that when you use .ROW you’ll need to give all the items .TABLE defines, i.e. one full row. To give more or less bytes use .DATA.

Example:

    .TABLE word, byte, word
    .ROW $aabb, "H", $ddee

This is the same as

> .DW $aabb .DB “H” .DW $ddee

This is not a compulsory directive.

## 3.157. `.SDSCTAG 1.0, "DUNGEON MAN", "A wild dungeon exploration game", "Ville Helin"`

`.SDSCTAG` adds SDSC tag to your SMS/GG ROM file. The ROM size must be at least 8KB just like with `.COMPUTESMSCHECKSUM` and `.SMSTAG`. For more information about this header take a look at https://www.smspower.org/Development/SDSCHeader. Here’s an explanation of the arguments:

    .SDSCTAG {version number}, {program name}, {program release notes}, {program author}

Note that program name, release notes and program author can also be pointers to strings instead of being only strings (which WLA terminates with zero, and places them into suitable locations inside the ROM file). So:

    .SDSCTAG 0.8, PRGNAME, PRGNOTES, PRGAUTHOR
    ...
    PRGNAME:  .DB "DUNGEON MAN", 0
    PRGNOTES: .DB "A wild and totally crazy dungeon exploration game", 0
    PRGAUTHOR:.DB "Ville Helin", 0

works also. All strings supplied explicitly to `.SDSCTAG` are placed somewhere in `.BANK 0 SLOT 0`.:

    .SDSCTAG 1.0, "", "", ""
    .SDSCTAG 1.0, 0, 0, 0

are also valid, here `0` and `""` mean the user doesn’t want to use any descriptive strings. Version number can also be given as an integer, but then the minor version number defaults to zero.

`.SDSCTAG` also defines `.SMSTAG` (as it’s part of the SDSC ROM tag specification).

This is not a compulsory directive.

## 3.158. `.SECTION "Init" FORCE`

Section is a continuous area of data which is placed into the output file according to the section type and `.BANK` and `.ORG` directive values.

The example begins a section called `Init`. Before a section can be declared, `.BANK` and `.ORG` should be used unless WLA is in library file output mode. Library file’s sections must all be `FREE` ones. `.BANK` tells the bank number where this section will be later relocated into. `.ORG` tells the offset for the relocation from the beginning of `.BANK`.

It is also possible to supply `BANK`, `SLOT`, `BASE` and `ORG` or `ORGA` to `.SECTION` as follows:

    .SECTION "NoInheritedParameters" BASE $70 BANK 0 SLOT 1 ORGA $1000

You can put sections inside a namespace. For instance, if you put a section into a namespace called `bank0`, then labels in that section can be accessed with `bank0.label`. This is not necessary inside the section itself. The namespace directive should immediately follow the name:

    .SECTION "Init" NAMESPACE "bank0"

You can give the size of the section, if you wish to force the section to some specific size, the following way:

    .SECTION "Init" SIZE 100 FREE

It’s possible to force WLALINK to align the sections by giving the alignment as follows:

    .SECTION "Init" SIZE 100 ALIGN 4 FREE

If you need an offset from the alignment, use OFFSET:

    .SECTION "Init" SIZE 10 ALIGN 256 OFFSET 32 FREE

And if you want that WLA returns the `ORG` to what it was before issuing the section, put `RETURNORG` at the end of the parameter list:

    .SECTION "Init" SIZE 100 ALIGN 4 FREE RETURNORG

By default WLA advances the `ORG`, so, for example, if your `ORG` was `$0` before a section of 16 bytes, then the `ORG` will be `16` after the section.

Note also that if your section name begins with double underlines (e.g., `__UNIQUE_SECTION!!!`) the section will be unique in the sense that when WLALINK recieves files containing sections which share the same name, WLALINK will save only the first of them for further processing, all others are deleted from memory with corresponding labels, references and calculations.

If a section name begins with an exclamation mark (`!`) it tells WLALINK to not to drop it, even if you use WLALINK’s ability to discard all unreferenced sections and there are no references to the section. You can achieve the same effect by adding `KEEP` to the end of the list:

    .SECTION "Init" SIZE 100 ALIGN 4 FREE RETURNORG KEEP

`FORCE` after the name of the section tells WLA that the section must be inserted so it starts at `.ORG`. `FORCE` can be replaced with `FREE` which means that the section can be inserted somewhere in the defined bank, where there is room. You can also use `OVERWRITE` to insert the section into the memory regardless of data collisions. Using `OVERWRITE` you can easily patch an existing ROM image just by `.BACKGROUND`’ing the ROM image and inserting `OVERWRITE` sections into it. `SEMIFREE` sections are also possible and they behave much like `FREE` sections. The only difference is that they are positioned somewhere in the bank starting from `.ORG`. `SEMISUBFREE` sections on the other hand are positioned somewhere in the bank starting from `$0` and ending to `.ORG`.

`SUPERFREE` sections are also available, and they will be positioned into the first suitable place inside the first suitable bank (candidates for these suitable banks have the same size with the slot of the section, no other banks are considered). You can also leave away the type specifier as the default type for the section is `FREE`.

If you wish to specify the banks where the section could be inserted into, use `SEMISUPERFREE` (and `BANKS` to specify the banks list):

    .SECTION "IAmABankedSection" SEMISUPERFREE BANKS 15-13/10/6-9/3/1

The banks list in the example unrolls into this: [ 15, 14, 13, 10, 6, 7, 8, 9, 3, 1 ]. The banks are inspected for free space in the given order.

You can name the sections as you wish, but there is one special name. A section called `BANKHEADER` is placed in the front of the bank where it is defined. These sections contain data that is not in the memory map of the machine, so you can’t refer to the data of a `BANKHEADER` section, but you can write references to outside. So no labels inside `BANKHEADER` sections. These special sections are useful when writing e.g., MSX programs. Note that library files don’t take `BANKHEADER` sections.

Here’s an example of a `BANKHEADER` section:

    .BANK 0
    .ORG 0
    .SECTION "BANKHEADER"
        .DW MAIN
        .DW VBI
    .ENDS

    .SECTION "Program"
    MAIN: CALL MONTY_ON_THE_RUN
    VBI:  PUSH HL
          ...
          POP HL
          RETI
    .ENDS

Here’s an example of an ordinary section:

    .BANK 0
    .ORG $150
    .SECTION "Init" FREE PRIORITY 1000
            DI
            LD  SP, $FFFE
            SUB A
            LD  ($FF00+R_IE), A
    .ENDS

This tells WLA that a `FREE` section called `Init` must be located somewhere in bank `0` and it has a sorting `PRIORITY` of 1000. If you replace `FREE` with `SEMIFREE` the section will be inserted somewhere in the bank `0`, but not in the `$0` - `$14F` area. If you replace `FREE` with `SUPERFREE` the section will be inserted somewhere in any bank with the same size as bank `0`.

Here’s the order in which WLALINK writes the sections:

1. `FORCE`

2. `SEMISUPERFREE`

3. `SEMISUBFREE`

4. `SEMIFREE`

5. `FREE`

6. `SUPERFREE`

7. `OVERWRITE`

You can change this order using `[sectionwriteorder]` in a link file.

Before the sections are inserted into the output file, they are sorted by priorities, so that the section with the highest priority is processed first. If priorities are the same, then the size of the section matters, and bigger sections are processed before smaller ones. The default `PRIORITY`, when not explicitly given, is 0. Note that `PRIORITY` accepts negative values as well.

You can use `AUTOPRIORITY` instead of `PRIORITY` when you want to assign descending priority to sections. Using this you can make it so that e.g., `APPENDTO` sections are appended in the lexical parsing order. `AUTOPRIORITY` starts from 65535 and is subtracted by one every time it’s used.

You can also create a RAM section. For more information about them, please read the `.RAMSECTION` directive explanation.

It is also possible to merge two or more sections using `APPENDTO`:

    .SECTION "Base"
    .DB 0
    .ENDS

    .SECTION "AppendToBase" FREE RETURNORG APPENDTO "Base"
    .DB 1
    .ENDS

And you can force a section to be placed after another section, with an offset:

    .SECTION "Follower" OFFSET 32 AFTER "Base"
    .DB 111
    .ENDS

If you want to force WLALINK to place a section say between $0100 and $0200 in the address space, use `WINDOW` (note that `.SLOT` must be used to make this placement possible, have the `.SECTION` in the correct slot):

    .SECTION "SpecialStuff" FREE WINDOW $0100 $0200
    NOP
    .ENDS

If you want to position a `.SECTION` so that it is placed in memory in a spot where e.g., only the least 8 bits of the address change (the `.SECTION` must thus be less than 256 bytes in size), use `BITWINDOW`:

    .SECTION "PageX" FREE BITWINDOW 8
    NOP
    .ENDS

This is not a compulsory directive.

## 3.159. `.SEED 123`

Seeds the random number generator.

The random number generator is initially seeded with the output of `time()`, which is, according to the manual, the time since the Epoch (00:00:00 UTC, January 1, 1970), measured in seconds. So if you don’t `.SEED` the random number generator yourself with a constant value, `.DBRND` and `.DWRND` give you different values every time you run WLA.

In WLA DX 9.4a and before we used the stdlib’s `srand()` and `rand()` functions making the output differ on different platforms. Since v9.4 WLA DX contains its own Mersenne Twister pseudo random number generator.

This is not a compulsory directive.

## 3.160. `.SEEDRANDOM`

Seeds the random number generator with the output of `time()`, which is, according to the manual, the time since the Epoch (00:00:00 UTC, January 1, 1970), measured in seconds.

By default the (pseudo) random number generator is seeded with `time()`, so you don’t have to do it yourself, but just in the case you want to do it somewhere in the source code, use this.

This is not a compulsory directive.

## 3.161. `.SHIFT`

Shifts the macro arguments one down (`\2` becomes `\1`, `\3` becomes `\2`, etc.). `.SHIFT` can thus only be used inside a `.MACRO`.

This is not a compulsory directive.

## 3.162. `.SLOT 1`

Changes the currently active memory slot. This directive is meant to be used with `SUPERFREE` sections, where only the slot number is constant when placing the sections.

You can use the number, address or name of the slot here:

    .SLOT 1           ; Use slot 1.
    .SLOT $2000       ; Use a slot with starting address of $2000.
    .SLOT "SlotOne"   ; Use a slot with a name "SlotOne"

This is not a compulsory directive.

## 3.163. `.SLOWROM`

Clears the ROM memory speed bit in `$FFD5` (`.HIROM`), `$7FD5` (`.LOROM`) or `$FFD5` and `$40FFD5` (`.EXHIROM`) to indicate that the SNES ROM chips are 200ns chips.

This is not a compulsory directive.

## 3.164. `.SMC`

Forces WLALINK to compute a proper SMC header for the ROM file.

SMC header is a chunk of 512 bytes. WLALINK touches only its first three bytes, and sets the rest to zeroes. Here’s what will be inside the first three bytes:

Byte | Description
`0` | low byte of 8KB page count.
`1` | high byte of 8KB page count.
`2` | Bit `7`: `0` Bit `6`: `0` Bit `5`: `0` = LoROM, `1` = HiROM Bit `4`: `0` = LoROM, `1` = HiROM Bit `3` and `2`: SRAM size (`00` = 256Kb, `01` = 64Kb, `10` = 16Kb, `11` = 0Kb) Bit `1`: `0` Bit `0`: `0`

This is not a compulsory directive.

## 3.165. `.NGHEADER`

Defines the Neo Geo cartridge header in `$100-$185` and, when needed, emits a default security code immediately after it. All fields are optional except for `NGH` and `USERENTRY`. Here are the default values:

    .NGHEADER
        NGH $1234
        SYSTEMVERSION 0
        PROMSIZE AUTO
        BACKUPRAMPTR 0
        BACKUPRAMSIZE 0
        EYECATCHER SYSTEM
        LOGOBANK $1B
        JPCONFIG 0
        USCONFIG 0
        EUCONFIG 0
        USERENTRY Start
        PLAYERSTART Start
        DEMOEND Start
        COINSOUND Start
        SECURITYCODEPTR *generated internal label*
    .ENDNG

`EYECATCHER` accepts `SYSTEM`, `GAME` and `NONE` as symbolic values. `PROMSIZE AUTO` uses the configured total P ROM size from the active ROM bank configuration. `PROMSIZE AUTOPOW2` rounds that size up to the next power-of-two MiB, writes the rounded size to the header, and pads the linked ROM image with `.EMPTYFILL` bytes to match.

Two optional fields extend the header for Neo Geo CD builds:

- `SYSTEM CART` / `SYSTEM CD` - convenience alias for `SYSTEMVERSION`; sets the system byte at `$107` to `0` (cartridge) or `2` (CD). An integer value is also accepted.

- `CDDACMDPTR <word>` - when present, emits a big-endian 16-bit Z80 RAM address at `$13A`. This is the CDDA command pointer read by the Neo Geo CD BIOS. Required only for CD builds.

This is not a compulsory directive.

## 3.166. `.NGSOFTDIP`

Emits a 128-byte Neo Geo BIOS soft-DIP / configuration-menu block at the current assembly position, formatted to match the layout expected by the `JPCONFIG` / `USCONFIG` / `EUCONFIG` pointers in `.NGHEADER`. Place a label immediately before the directive and pass that label to the matching `.NGHEADER` config field. `NAME` is required; every other field defaults to a blank / `$FF` / `$00` fill. Example:

    SoftDIPJP:
    .NGSOFTDIP
        NAME "TEST GAME"
        SPECIAL $FF,$FF,$FF,$FF,$FF,$FF
        OPTIONS $24,$02,$00,$00,$00,$00,$00,$00,$00,$00
        TEXT "LIVES       "
        TEXT "1           "
        TEXT "2           "
        TEXT "3           "
        TEXT "4           "
        TEXT "HOW TO PLAY "
        TEXT "WITH        "
        TEXT "WITHOUT     "
    .ENDNGSOFTDIP

The block layout is:

- 16 bytes - game name (upper ASCII, padded with `$20`).

- 6 bytes - `SPECIAL` list (default `$FF` x 6).

- 10 bytes - `OPTIONS` list (default `$00` x 10).

- 8 x 12 bytes - `TEXT` menu labels (default 12 spaces each).

Fewer than eight `TEXT` entries is allowed; remaining lines are padded with spaces.

This is not a compulsory directive.

## 3.167. `.NGVECTORS`

Emits three absolute `jmp` instructions for the Neo Geo interrupt-vector stub table at the current assembly position. Place it at the vector stub location used by your startup code, usually with an absolute `.ORGA`. All three fields are required and may be labels, numeric addresses or calculated addresses. The emitted order is always `VBLANK`, `TIMER`, `EXTERNAL`:

    .ORGA $0066
    .NGVECTORS
        VBLANK   VBlankHandler
        TIMER    TimerHandler
        EXTERNAL ExternalHandler
    .ENDNGVECTORS

This directive emits code only; it does not install interrupt handlers or enable interrupts.

This is not a compulsory directive.

## 3.168. `.MDVECTORS`

Defines the Sega Mega Drive/Genesis MC68000 exception and interrupt vector table at `$000000-$0000FF`. `RESET` is required. `INITIALSP` / `SSP` defaults to `$00FFFE00` and every other unspecified entry uses `DEFAULT` when it is present, or `$00000000` otherwise. Pointer fields accept labels, numeric addresses and calculated addresses:

    .MDVECTORS
        RESET   Start
        DEFAULT DefaultException
        HBLANK  HBlankHandler
        VBLANK  VBlankHandler
    .ENDMDVECTORS

Recognized vector names are `INITIALSP` / `SSP`, `RESET`, `BUSERROR`, `ADDRESSERROR` / `ADDRERROR`, `ILLEGALINSTR` / `ILLEGAL`, `ZERODIVIDE` / `DIVZERO`, `CHKINSTR` / `CHK`, `TRAPV`, `PRIVVIOLATION` / `PRIVILEGE`, `TRACE`, `LINEA` / `LINE1010`, `LINEF` / `LINE1111`, `SPURIOUS`, `LEVEL1`, `EXTERNAL` / `LEVEL2`, `LEVEL3`, `HBLANK` / `LEVEL4`, `LEVEL5`, `VBLANK` / `LEVEL6`, `LEVEL7` and `TRAP0` through `TRAP15`. Do not also place code or data at `$000000` with `.ORG 0` or `.ORGA 0`; `.MDVECTORS` owns the cartridge vector-table range.

This is not a compulsory directive.

## 3.169. `.MCDHEADER`

Defines a Sega CD / Mega CD main CPU initial-program header at `$000000`. All fixed string fields are padded with spaces. `IPSTART` is required; other pointer fields default to `0`:

    .MCDHEADER
        SYSTEMTYPE "SEGADISCSYSTEM"
        COPYRIGHT "WLA DX"
        TITLEDOMESTIC "WLA DX MEGA CD MAIN"
        TITLEOVERSEAS "WLA DX SEGA CD MAIN"
        SERIALNUMBER "GM 00000000-00"
        DEVICESUPPORT "J"
        REGIONSUPPORT "JUE"
        IPSTART Start
        SPSTART SubCpuProgram
        VBLANKINT VBlankHandler
        HBLANKINT HBlankHandler
        USERPROCESS UserProcess
    .ENDMCDHEADER

String widths are `SYSTEMTYPE` 16 bytes, `COPYRIGHT` 16 bytes, `TITLEDOMESTIC` 48 bytes, `TITLEOVERSEAS` 48 bytes, `SERIALNUMBER` 14 bytes, `DEVICESUPPORT` 16 bytes and `REGIONSUPPORT` 3 bytes. Close the block with `.ENDMCDHEADER`. `.MCDHEADER` and `.MCDSPHEADER` cannot be used in the same source file. If `DEVICESUPPORT` is omitted, WLA DX emits a warning and uses `"J"` padded to the 16-byte field width. The field order follows the IP.BIN boot record layout documented in Sega’s Mega CD technical bulletins. For standard cartridge header background, see https://plutiedev.com/rom-header; for Sega CD images, use `.MCDHEADER` instead of `.SMDHEADER`.

This is not a compulsory directive.

## 3.170. `.MCDSPHEADER`

Defines a Sega CD / Mega CD sub CPU program header at `$000000`. `SPENTRY` is required; the remaining pointer fields default to `0`:

    .MCDSPHEADER
        SPENTRY SubEntry
        SPINIT SubInit
        SPMAIN SubMain
        SPINT2 SubInt2
        SPUSER SubUser
    .ENDMCDSPHEADER

Close the block with `.ENDMCDSPHEADER`. `.MCDHEADER` and `.MCDSPHEADER` cannot be used in the same source file. The field order follows the SP.BIN boot record layout documented in Sega’s Mega CD technical bulletins.

This is not a compulsory directive.

## 3.171. `.SMDHEADER`

Defines the Sega Mega Drive ROM header in `$100-$1FF`. All the fields in `.SMDHEADER` are optional. Here are the default values:

    .SMDHEADER
        SYSTEMTYPE "SEGA MEGA DRIVE "    ; 16 bytes
        COPYRIGHT  "                "    ; 16 bytes
        TITLEDOMESTIC "             "    ; 48 bytes (all spaces)
        TITLEOVERSEAS "             "    ; 48 bytes (all spaces)
        SERIALNUMBER  "             "    ; 14 bytes (all spaces)
        DEVICESUPPORT "J            "    ; 16 bytes ('J' and the rest are spaces)
        ROMADDRESSRANGE $0, -1           ;  8 bytes (-1 is turned into ROM size minus one)
        RAMADDRESSRANGE $FF0000, $FFFFFF ;  8 bytes
        EXTRAMEMORY "RA", $A0, $20, S, E ; 12 bytes (S and E and start and end, both 0)
        MODEMSUPPORT "            "      ; 12 bytes (all spaces)
        REGIONSUPPORT "JUE"              ;  3 bytes
    .ENDSMD

When `.SMDHEADER` is defined, also the ROM checksum is calculated.

See https://plutiedev.com/rom-header for more information about the SMD header.

This is not a compulsory directive.

## 3.172. `.SMSHEADER`

All the fields in `.SMSHEADER` are optional and PRODUCTCODE, VERSION, REGIONCODE and RESERVEDSPACE default to zero. If ROMSIZE is not specified it will be calculated automatically:

    .SMSHEADER
        PRODUCTCODE 26, 70, 2 ; 2.5 bytes
        VERSION 1             ; 0-15
        REGIONCODE 4          ; 3-7
        RESERVEDSPACE 0, 0    ; 2 bytes
        ROMSIZE 0             ; 0-15
        CHECKSUMSIZE 32*1024  ; Uses the first this-many bytes in checksum
                              ;   calculations (excluding header area)
        FORCECHECKSUM $1234   ; Forces the checksum to be this value
        BASEADDRESS $1FF0     ; Write the header at this address
    .ENDSMS

The `REGIONCODE` also defines the system:

`3` | SMS Japan
`4` | SMS Export
`5` | GG Japan
`6` | GG Export
`7` | GG International

When `.SMSHEADER` is defined, also the checksum is calculated, and TMR SEGA, two reserved bytes and ROM size are defined.

See http://www.smspower.org/Development/ROMHeader for more information about SMS header.

This is not a compulsory directive.

## 3.173. `.SMSTAG`

`.SMSTAG` forces WLA to write an ordinary SMS/GG ROM tag to the ROM file. Currently only the string `TMR SEGA` and ROM checksum are written (meaning that `.SMSTAG` also defines `.COMPUTESMSCHECKSUM`). The ROM size must be at least 8KBs.

This is not a compulsory directive.

## 3.174. `.SNESEMUVECTOR`

Begins definition of the emulation mode interrupt vector table:

    .SNESEMUVECTOR
    COP    COPHandler
    UNUSED $0000
    ABORT  BRKHandler
    NMI    VBlank
    RESET  Main
    IRQBRK IRQBRKHandler
    .ENDEMUVECTOR

These can be defined in any order, but they will be placed into memory starting at `$7FF4` (`$FFF4` in HiROM, `$40FFF4` and `$FFF4` in ExHiROM) in the order listed above. All the vectors default to `$0000`.

This is not a compulsory directive.

## 3.175. `.SNESHEADER`

This begins the SNES header definition, and automatically defines `.COMPUTESNESCHECKSUM`. From here you may define any of the following:

- `ID "ABCD"` - inserts a one to four letter string starting at `$7FB2` (lorom) or `$FFB2` (hirom).

- `NAME "Hello World!"` - identical to a freestanding `.NAME`.

- `LOROM` - identical to a freestanding `.LOROM`.

- `HIROM` - identical to a freestanding `.HIROM`.

- `EXHIROM` - identical to a freestanding `.EXHIROM`.

- `SLOWROM` - identical to a freestanding `.SLOWROM`.

- `FASTROM` - identical to a freestanding `.FASTROM`.

- `CARTRIDGETYPE $00` - Places the given 8-bit value in `$7FD6` (`$FFD6` in HiROM, `$40FFD6` and `$FFD6` in ExHiROM). Some possible values I’ve come across but cannot guarantee the accuracy of:

  > `$00` | ROM |  |
  > `$01` | ROM | RAM |
  > `$02` | ROM | SRAM |
  > `$03` | ROM |  | DSP1
  > `$04` | ROM | RAM | DSP1
  > `$05` | ROM | SRAM | DSP1
  > `$13` | ROM |  | Super FX

- `ROMSIZE $09` - Places the given 8-bit value in `$7FD7` (`$FFD7` in HiROM, `$40FFD7` and `$FFD7` in ExHiROM). Possible values include (but may not be limited to):

  > `$08` | 2 Megabits
  > `$09` | 4 Megabits
  > `$0A` | 8 Megabits
  > `$0B` | 16 Megabits
  > `$0C` | 32 Megabits

- `SRAMSIZE $01` - Places the given 2-bit value into `$7FD8` (`$FFD8` in HiROM, `$40FFD8` and `$FFD8` in ExHiROM). I believe these are the only possible values:

  > `$00` | 0 kilobits
  > `$01` | 16 kilobits
  > `$02` | 32 kilobits
  > `$03` | 64 kilobits

- `COUNTRY $00` - Places the given 8-bit value into `$7FD9` (`$FFD9` in HiROM, `$40FFD9` and `$FFD9` in ExHiROM). `$00` is Japan and `$01` is the United States, and there several more for other regions that I cannot recall off the top of my head.

- `LICENSEECODE $00` - Places the given 8-bit value into `$7FDA` (`$FFDA` in HiROM, `$40FFDA` and `$FFDA` in ExHiROM). You must find the legal values yourself as there are plenty of them. ;)

- `VERSION $01` - Places the given 8-bit value into `$7FDB` (`$FFDB` in HiROM, `$40FFDB` and `$FFDB` in ExHiROM). This is supposedly interpreted as version 1.byte, so a `$01` here would be version 1.01.

This is not a compulsory directive.

## 3.176. `.SNESNATIVEVECTOR`

Begins definition of the native mode interrupt vector table:

    .SNESNATIVEVECTOR
    COP    COPHandler
    BRK    BRKHandler
    ABORT  ABORTHandler
    NMI    VBlank
    UNUSED $0000
    IRQ    IRQHandler
    .ENDNATIVEVECTOR

These can be defined in any order, but they will be placed into memory starting at `$7FE4` (`$FFE4` in HiROM, `$40FFE4` and `$FFE4` in ExHiROM) in the order listed above. All the vectors default to `$0000`.

This is not a compulsory directive.

## 3.177. `.STRINGMAP script "Hello\n"`

After you’ve given the `.STRINGMAPTABLE`, use `.STRINGMAP` to define bytes using the mapping in `.STRINGMAPTABLE`. For example:

    .STRINGMAP script, "いうえA\n"

`.STRINGMAP` with `.STRINGMAPTABLE` is an alternative way of mapping characters to `.ASC` and `.ASCIITABLE`. Also note that here the result and the source of the mapping can be more than just one byte.

This is not a compulsory directive.

## 3.178. `.STRINGMAPTABLE script "script.tbl"`

`.STRINGMAPTABLE`’s only purpose is to provide string mapping for `.STRINGMAP`. Take a look at the example:

    .STRINGMAPTABLE script "script.tbl"

This will load the file “script.tbl” and define a new string mapping called “script”. This file is in the “table file” format commonly used for game translations; take a look at an example of one:

    00=A
    01=B
    ; This is a comment
    ff01=あ
    ff02=いうえ
    fe=\n

The values to the left of the ‘=’ are a variable number of bytes expressed in hex, which map to the text value on the right. Note that depending on the text encoding of the file, this may be a variable number of bytes too. Thus this is a more flexible version of `.ASCIITABLE`.

After you’ve given the `.STRINGMAPTABLE`, use `.STRINGMAP` to define bytes using this mapping. For example:

    .STRINGMAP script, "いうえA\n"

This will map to the byte values `FF 02 00 FE`, provided the source file and TBL file use the same string encoding - use of UTF-8 is advised.

Note that all characters must be defined in the mapping - there is no fallback to ASCII encoding. You also cannot mix in byte values like with `.DB` and `.ASC`.

You can define multiple named string map tables.

This is not a compulsory directive.

## 3.179. `.STRUCT enemy_object`

Begins the definition of a structure. These structures can be placed inside `RAMSECTION` s and `ENUM` s. Here’s an example:

    .STRUCT enemy_object
    id      dw             ; the insides of a .STRUCT are 1:1 like in .ENUM
    x       db             ; except that no structs inside structs are
    y       db             ; allowed.
    data    ds  10
    info    dsb 16
    stats   dsw  4
    .ENDST

This also creates a definition `_sizeof_[struct name]`, in our example this would be `_sizeof_enemy_object`, and the value of this definition is the size of the object, in bytes (2+1+1+10+16+4*2 = 38 in the example).

You’ll get the following definitions as well:

    enemy_object.id    (== 0)
    enemy_object.x     (== 2)
    enemy_object.y     (== 3)
    enemy_object.data  (== 4)
    enemy_object.info  (== 14)
    enemy_object.stats (== 30)

After defining a `.STRUCT` you can create an instance of it in a `.RAMSECTION` / `.ENUM` by typing:

    <instance name> INSTANCEOF <struct name> [optional, the number of structures]

Here’s an example:

    .RAMSECTION "enemies" BANK 4 SLOT 4
    enemies   INSTANCEOF enemy_object 4
    enemyman  INSTANCEOF enemy_object
    enemyboss INSTANCEOF enemy_object
    .ENDS

This will create definitions like `enemies`, `enemies.1.id`, `enemies.1.x`, `enemies.1.y` and so on. Definition `enemies` is followed by four `enemy_object` instances. After those four come `enemyman` and `enemyboss` instances, but as they are single instances, their definitions lack the index: `enemyman`, `enemyman.id`, `enemyman.x`, `enemyman.y` and so on.

Take a look at the documentation on `.RAMSECTION` & `.ENUM`, they have more examples of how you can use `.STRUCT` s.

A WORD OF WARNING: Don’t use labels `b`, `B`, `w` and `W` inside a structure as e.g., WLA sees `enemy.b` as a byte sized reference to enemy. All other labels should be safe:

    lda enemy1.b  ; load a byte from zeropage address enemy1 or from the address
                  ; of enemy1.b??? i can't tell you, and WLA can't tell you...

It’s possible to explicitly define the size of the `.STRUCT` by using keyword `SIZE`:

    .STRUCT PaddedStruct SIZE 8
    posX  DW
    posY  DW
    .ENDST

Normally this `.STRUCT` would define four bytes, but by using keyword `SIZE` its size is now eight bytes. The extra padding, put after the last item in the `.STRUCT`, will contain `.EMPTYFILL` bytes when used with `.DSTRUCT`.

Note that if we `.DSTRUCT` “PaddedStruct” and name it PS1 we’ll also get a definition

> _paddingof_PS1 (== 4)

This is not a compulsory directive.

## 3.180. `.SYM SAUSAGE`

WLA treats symbols (`SAUSAGE` in this example) like labels, but they only appear in the symbol files WLALINK outputs. Useful for finding out the location where WLALINK puts data.

This is not a compulsory directive.

## 3.181. `.SYMBOL SAUSAGE`

`.SYMBOL` is an alias for `.SYM`.

This is not a compulsory directive.

## 3.182. `.TABLE byte, word, byte`

Defines table’s columns. With .DATA and .ROW you can define data much like using .DB or .DW, but .TABLE makes it convenient to feed big amounts of data in mixed format.

For example:

    .TABLE byte, word, byte

After the columns have been defined, you can define rows using e.g.,

> .ROW $01, $0302, $04

This is the same as:

    .DB $01
    .DW $0302
    .DB $04

Note that .DATA can also be used instead of .ROW, if one wants to give the data in pieces.

All supported column formats:

  - DB, BYT, BYTE

  - DW, WORD, ADDR

  - DL, LONG, FARADDR

  - DD

  - DS, DSB

  - DSW

  - DSL

  - DSD

This is not a compulsory directive.

## 3.183. `.UNBACKGROUND $1000 $1FFF`

After issuing `.BACKGROUND` you might want to free some parts of the backgrounded ROM image for e.g., `FREE` sections. With `.UNBACKGROUND` you can define such regions. In the example a block starting at `$1000` and ending at `$1FFF` was released (both ends included). You can issue `.UNBACKGROUND` as many times as you wish.

This is not a compulsory directive.

## 3.184. `.UNDEF DEBUG`

`.UNDEF` is an alias for `.UNDEFINE`.

This is not a compulsory directive.

## 3.185. `.UNDEFINE DEBUG`

Removes the supplied definition label from system. If there is no such label as given no error is displayed as the result would be the same.

You can undefine as many definitions as you wish with one `.UNDEFINE`:

    .UNDEFINE NUMBER, NAME, ADDRESS, COUNTRY
    .UNDEFINE NAME, AGE

This is not a compulsory directive.

## 3.186. `.UNION name`

Begins a “union”. This can only be used in `.ENUM` s, `.RAMSECTION` s and `.STRUCT` s.

When entering a union, the current address in the enum is saved, and the following data is processed as normal. When the `.NEXTU` directive is encountered, the address is reverted back to the start of the union. This allows one to assign an area of memory to multiple labels:

    .ENUM $C000
        .UNION
            pos_lowbyte:  db
            pos_highbyte: db
            extra_word:   dw
        .NEXTU
            pos:          dw
        .ENDU
        after: db
    .ENDE

This example is equivalent to:

    .DEFINE pos_lowbyte  $c000
    .DEFINE pos_highbyte $c001
    .DEFINE extra_word   $c002
    .DEFINE pos          $c000
    .DEFINE after        $c004

The `.UNION` and `.NEXTU` commands can be given an argument to assign a prefix to the labels that follow:

    .ENUM $C000
        .UNION union1
            byte1: db
            byte2: db
        .NEXTU union2
            word1: dw
        .ENDU
    .ENDE

This example is equivalent to:

    .DEFINE union1.byte1 $c000
    .DEFINE union1.byte2 $c001
    .DEFINE union2.word1 $c000

Unions can be nested.

## 3.187. `.VERSION 1`

Indicates the Mask ROM version number located at `$14C` of a Gameboy ROM.

This is not a compulsory directive.

## 3.188. `.WDC`

Turns WLA-65816 into a mode where it accepts WDC standard assembly code, in addition to WLA’s own syntax. In WDC standard mode:

    AND <x  ; 8-bit
    AND |?  ; 16-bit
    AND >&  ; 24-bit

are the same as:

    AND x.b ; 8-bit
    AND ?.w ; 16-bit
    AND &.l ; 24-bit

in WLA’s own syntax. Beware of the situations where you use ‘<’ and ‘>’ to get the low and high bytes!

This is not a compulsory directive.

## 3.189. `.WHILE COUNTER > 0`

Repeats the text enclosed between `.WHILE <CONDITION>` and `.ENDR`:

    .WHILE COUNTER > 0
    .DB COUNTER
    .REDEFINE COUNTER = COUNTER - 1
    .ENDR

This is not a compulsory directive.

## 3.190. `.WORD 16000, 10, 255`

`.WORD` is an alias for `.DW`.

This is not a compulsory directive.

# 4. Assembler Syntax

## 4.1. Case Sensitivity

WLA is case sensitive, except with directives, so be careful.

## 4.2. Comments

Comments begin with `;` or `*` and end along with the line. `;` can be used anywhere, but `*` can be placed only at the beginning of a new line.

WLA supports also ANSI C style commenting. This means you can start a multiline comment with `/*` and end it with `*/`.

What also is supported are C++ style comments. This means you can start a comment with `//`.

You can also use `.ASM` and `.ENDASM` directives to skip characters. These function much like ANSI C comments, but unlike the ANSI C comments these can be nested.

## 4.3. Line splitting

Lines can be split using a `\` between elements. So instead of writing

> .db 1, 2, 3, 4, 5, 6, 7, 8

it’s possible to write

> .db 1, 2, 3, 4 \

>   5, 6, 7, 8

Note that line splitting works only in places where WLA expects a new label, number, calculation, etc. String splitting isn’t currently supported.

## 4.4. Using Commas

In many places it’s possible to give parameters without commas between them:

    .db 1 2 3 4 5 ; 01 02 03 04 05

CAVEAT! CAVEAT! CAVEAT!

If you specify the following

> .db 1 -2 3 -4 5 ; FF FF 05

WLA will detect and compute calculations, so to be sure, always use commas:

    .db 1, -2, 3, -4, 5 ; 01 FE 03 FC 05

## 4.5. Labels

Labels are ordinary strings (which can also end with a `:`). Labels starting with `_` are considered to be local labels and do not show outside sections where they were defined, or outside object files, if they were not defined inside a section.

Here are few examples of different labels:

    VBI_IRQ:
    VBI_IRQ2
    _VBI_LOOP:
    main:

Labels starting with `@` are considered to be child labels. They can only be referenced within the scope of their parent labels, unless the full name is specified. When there is more than one `@`, the label is considered to be a child of a child.

Here are some examples of child labels:

    PARENT1:
    @CHILD:
    @@SUBCHILD

    PARENT2:
    @CHILD:

This is legal, since each of the `@CHILD` labels has a different parent. You can specify a parent to be explicit, like so:

    jr PARENT1@CHILD@SUBCHILD

You can also use `__label__` to refer to the last defined parent label:

    main:                 ; #
            nop
            nop
    @child:
            nop
            nop
    @@grandchild:
            nop
            nop
            jmp __label__ ; jump -> #
    loop:   nop           ; %
            nop
            jmp __label__ ; jump -> %

Note that when you place `:` in front of the label string when referring to it, you’ll get the bank number of the label, instead of the label’s address. Here’s an example:

    LD A, :LOOP
    .BANK 2 SLOT 0
    LOOP:

Here `LD A, :LOOP` will be replaced with `LD A, 2` as the label `LOOP` is inside the bank number two.

When you are referring to a label and you are adding something to its address (or subtracting, any arithmetics apply) the result will always be bytes.

    .org 20
    DATA:  .dw 100, 200, 300
           ld  a, DATA+1
                  ^^^^^^ = r

So here the result `r` will be the address of `DATA` plus one, here 21. Some x86 assemblers would give here `22` as the result `r` as `DATA` points to an array or machine words, but WLA isn’t that smart (and some people including me think this is the better solution).

Note that each CPU WLA supports contains opcodes that either generate an absolute reference or a relative reference to the given label. For example,

    .org 20
    DATA:  ld  a, DATA   ; DATA becomes 20 (absolute)
           jr  DATA      ; DATA becomes -4 (relative)

Check out section 14 for the list of opcodes that generate relative references.

You can also use `-`, `--`, `---`, `+`, `++`, `+++`, … as un-named labels. Labels consisting of `-` are meant for reverse jumps and labels consisting of `+` are meant for forward jumps. You can reuse un-named labels as much as you wish inside your source code. Here’s an example of this:

        dec e
        beq ++      ; jump -> ?
        dec e
        beq +       ; jump -> %
        ld d, 14
    --- ld a, 10    ; !
    --  ld b, c     ; #
    -   dec b       ; *
        jp nz, -    ; jump -> *
        dec c
        jp nz, --   ; jump -> #
        dec d
        jp nz, ---  ; jump -> !
        ld a, 20
    -   dec a       ; $
        jp nz, -    ; jump -> $
    +   halt        ; %
    ++  nop         ; ?

Note that `__` (that’s two underline characters) serves also as a un-named label. You can refer to this label from both directions. Use `_b` when you are jumping backwards and `_f` when you are jumping forwards label `__`.

Example:

       dec e
       jp z, _f     ; jump -> *
       dec e
    __ ldi a, (hl)  ; *
       dec e
       jp nz, _b    ; jump -> *

CAVEAT! CAVEAT! CAVEAT!

The following code doesn’t work as it would if WLA would determine the distance lexically (but in practice it’s WLALINK that does all the calculations and sees only the preprocessed output of WLA):

    .macro dummy
    -  dec a        ; #
       jp nz, -     ; jump -> #
    .endm

       ...
    -  nop          ; *
       dummy
       dec e
       jp nz, -     ; i'd like to jump to *, but i'll end up jumping
                    ; to # as it's closest to me in the output WLA produces
                    ; for WLALINK (so it's better to use \@ with labels inside
                    ; a macro).

To make un-named labels inside a `.MACRO` isolated, and the previous example to work, use the keyword `ISOLATED`

    .macro dummy isolated
    -  dec a        ; #
       jp nz, -     ; jump -> #
    .endm

The same issue exists with child labels. See `.MACRO`’s documentation for more details.

WLALINK will also generate `_sizeof_[label]` defines that measure the distance between two consecutive labels. These labels have the same scope as the labels they describe. Here is an example:

    Label1:
        .db 1, 2, 3, 4
    Label2:

In this case you’ll get a definition `_sizeof_Label1` that will have value `4`.

WLA will skip over any child labels when calculating `_sizeof`. So, in this example:

    Label1:
    .db 1, 2
    @child:
        .db 3, 4
    Label2:

The value of `_sizeof_Label1` will still have a value of `4`.

NOTE: If your code is outside `.SECTION` s then an empty byte in the output will mark the end of the `_sizeof_[label]`. Example:

> .ORG $0000 Label1: .db 1, 2, 3

> .ORG $0100 Label2: .db 4, 5

Here `_sizeof_Label1` will be 3 as there is empty space between $0003 - $0100.

## 4.6. Number Types

`1000` | decimal
`$100` | hexadecimal
`100h` | hexadecimal
`0x10` | hexadecimal
`%100` | binary
`0b10` | binary
`'x'` | character

Remember that if you use the suffix `h` to give a hexadecimal value, and the value begins with an alphabet, you must place a zero in front of it so WLA knows it’s not a label (e.g., `0ah` instead of `ah`).

## 4.7. Strings

Strings begin with and end to `"`. Note that no `0` is inserted to indicate the termination of the string like in e.g., ANSI C. You’ll have to do it yourself. You can place quotation marks inside strings the way C preprocessors accept them.

Here are some examples of strings:

    "Hello world!"
    "He said: \"Please, kiss me honey.\""

## 4.8. Substitution

It’s possible to substitute definition’s name with its value inside a label.

Here’s an example:

    .REPEAT 10 INDEX COUNT
    Label_{COUNT}:                      ; -> Label_0, Label_1, Label_2...
    .DW Label_{COUNT}
    .ENDR

Substitution supports minimal formatting for integers:

    .DEFINE COUNT = 10
    .DEFINE UNIT = 5
    Label_{%.4x{COUNT}}:                ; -> Label_000a
    Label_{%.3X{COUNT}}_{%.3X{UNIT}}:   ; -> Label_00A_005
    Label_{%.9d{COUNT}}:                ; -> Label_000000010
    Label_{%.3i{COUNT}}:                ; -> Label_010

The examples show all the formatting symbols currently supported.

The same substitution works for strings inside quotes when the quoted string is as follows:

    .db { "HELLO_{COUNT}" }             ; -> "HELLO_10"

Note that only WLA can do the substitution and it needs to know the value of the definition at the time the substitution is done, i.e., the time a string containing a substitution is parsed.

Also note that you can embed calculations into substitutions:

    .DEFINE COUNT = 1
    Label_{COUNT+1}:                    ; -> Label_2

It’s also possible to substitute text inside .MACROs:

    .MACRO INST_ABCD
       abcd.b d1, \1
    .ENDM

    INST_ABCD "d2"                      ; -> abcd.b d1, d2
    INST_ABCD "d7"                      ; -> abcd.b d1, d7

Note that this kind of substitution only works for lines with assembly instructions inside a .MACRO, it doesn’t work e.g., for lines with directive calls.

## 4.9. Mnemonics

You can give the operand size with the operand itself (and this is highly recommended) in WLA 6502/65C02/65CE02/HUC6280/65816/6800/6801/6809:

    and #20.b
    and #20.w
    bit loop.b
    bit loop.w

## 4.10. Brackets?

You can write

    LDI (HL), A

or

    LDI [HL], A

as both mean the same thing in the syntax of most of the supported CPUs. Yes, you could write

    LDI [HL), A

but that is not recommended.

Note that brackets have special meaning when dealing with a 65816/SPC-700 system so you can’t use

    AND [$65]

instead of

    AND ($65)

as they mean different things.

# 5. Error Messages

There are quite a few of them in WLA, but most of them are not as informative as I would like them to be. This will be fixed in the future. Mean while, be careful. ;)

# 6. Supported ROM/RAM/Cartridge Types (WLA-GB)

## 6.1. ROM Size

GB-Z80 version of WLA supports the following ROM bank sizes. There’s no such limit in the Cx4/Z80/Z80N/eZ80/6502/65C02/65CE02/65816/68000/6800/6801/6809/8008/8080/ HUC6280/SPC-700/SuperFX version of WLA. Supply one of the following values to `.ROMBANKS`.

`$00` | 256Kbit | 32KByte | 2 banks
`$01` | 512Kbit | 64KByte | 4 banks
`$02` | 1Mbit | 128KByte | 8 banks
`$03` | 2Mbit | 256KByte | 16 banks
`$04` | 4Mbit | 512KByte | 32 banks
`$05` | 8Mbit | 1MByte | 64 banks
`$06` | 16Mbit | 2MByte | 128 banks
`$07` | 32Mbit | 4MByte | 256 banks
`$08` | 64Mbit | 8MByte | 512 banks
`$52` | 9Mbit | 1.1MByte | 72 banks
`$53` | 10Mbit | 1.2MByte | 80 banks
`$54` | 12Mbit | 1.5MByte | 96 banks

## 6.2. RAM Size

Supply one of the following hex values to `.RAMSIZE` in the GB-Z80 version of WLA.

`$00` | None | None | None
`$01` | 16kbit | 2kByte | 1 bank
`$02` | 64kbit | 8kByte | 1 bank
`$03` | 256kbit | 32kByte | 4 banks
`$04` | 1Mbit | 128kByte | 16 banks
`$05` | 512kbit | 64kByte | 8 banks

## 6.3. Cartridge Type

It’s up to the user to check that the cartridge type is valid and can be used combined with the supplied ROM and RAM sizes. Give one the the following values to `.CARTRIDGETYPE` in the GB-Z80 version of WLA.

`$00` | ROM |  |  |  |  |
`$01` | ROM | MBC1 |  |  |  |
`$02` | ROM | MBC1 | RAM |  |  |
`$03` | ROM | MBC1 | RAM | BATTERY |  |
`$05` | ROM | MBC2 |  |  |  |
`$06` | ROM | MBC2 |  | BATTERY |  |
`$08` | ROM |  | RAM |  |  |
`$09` | ROM |  | RAM | BATTERY |  |
`$0B` | ROM | MMM01 |  |  |  |
`$0C` | ROM | MMM01 | SRAM |  |  |
`$0D` | ROM | MMM01 | SRAM | BATTERY |  |
`$0F` | ROM | MBC3 |  | BATTERY | TIMER |
`$10` | ROM | MBC3 | RAM | BATTERY | TIMER |
`$11` | ROM | MBC3 |  |  |  |
`$12` | ROM | MBC3 | RAM |  |  |
`$13` | ROM | MBC3 | RAM | BATTERY |  |
`$19` | ROM | MBC5 |  |  |  |
`$1A` | ROM | MBC5 | RAM |  |  |
`$1B` | ROM | MBC5 | RAM | BATTERY |  |
`$1C` | ROM | MBC5 |  |  |  | RUMBLE
`$1D` | ROM | MBC5 | SRAM |  |  | RUMBLE
`$1E` | ROM | MBC5 | SRAM | BATTERY |  | RUMBLE
`$20` | MBC6 |  |  |  |  |
`$22` | MBC7 |  |  |  |  |
`$BE` | Pocket Voice |  |  |  |  |
`$FC` | Pocket Camera |  |  |  |  |
`$FD` | Bandai TAMA5 |  |  |  |  |
`$FE` | Hudson HuC-3 |  |  |  |  |
`$FF` | Hudson HuC-1 |  |  |  |  |

# 7. eZ80 Support

WLA DX includes a Zilog eZ80 target named `wla-ez80`. The target keeps WLA’s Z80 syntax where possible and adds the documented eZ80 instruction set, including ADL-mode address and immediate handling.

## 7.1. ADL Mode And Suffixes

`.ADL ON` makes Z80-style 16-bit immediate and address operands assemble as 24-bit values where the eZ80 encoding allows it. `.ADL OFF` returns to the default Z80-compatible 16-bit behavior.

Per-instruction mode suffixes emit one prefix byte before the instruction and override the current ADL immediate width for that instruction:

- `.S` or `.SIS`: `40h`, short instruction and short immediate

- `.LIS`: `49h`, long instruction and short immediate

- `.SIL`: `52h`, short instruction and long immediate

- `.L` or `.LIL`: `5Bh`, long instruction and long immediate

The short `.S` and `.L` forms match manual entries that only override the instruction mode, such as `JP.S HL` and `JP.L IX`. For instructions with an immediate or absolute address operand, use the full `.SIS`, `.LIS`, `.SIL` or `.LIL` suffix when you want to state both the instruction and immediate mode explicitly.

Examples:

    .ADL ON
    jp $123456      ; C3 56 34 12
    jp.lis $1234    ; 49 C3 34 12
    jp.s hl         ; 40 E9
    jp.l ix         ; 5B DD E9

## 7.2. Instruction Coverage

The eZ80 target supports the documented Z80-compatible base instruction set and the documented eZ80 additions currently covered by WLA DX, including:

- `IN0` and `OUT0`

- `TST` and `TSTIO`

- `LEA` and `PEA`

- `MLT`, `SLP`, `STMIX` and `RSMIX`

- `LD A,MB` and `LD MB,A`

- eZ80 block I/O variants such as `INI2`, `IND2`, `INIM`, `INIRX`, `OTIM`, `OTDM` and `OTIRX`

- multibyte `LD` forms through `(HL)`, `(IX+d)` and `(IY+d)`

- documented `IXH`, `IXL`, `IYH` and `IYL` byte-register operations

The target intentionally does not expose WLA’s Z80-only per-register shadow aliases, `HX`/`LX`/`HY`/`LY` aliases, undocumented `SLL` forms, or DDCB/FDCB result-copy aliases.

## 7.3. Agon MOS Binaries

`wla-ez80` includes small source-level helpers for Agon MOS binaries. Include the flat Agon MOS memory map from `memorymaps/agon_mos.i` and the header macros from `include/agon/mos.inc`. The MOS metadata starts at byte `$40` and contains the bytes `"MOS", $00, mode` where mode is `$00` for Z80 mode or `$01` for ADL mode.

Example:

    .INCDIR "include/agon"
    .INCLUDE "memorymaps/agon_mos.i"
    .INCLUDE "mos.inc"

    .ROMBANKMAP
        BANKSTOTAL 1
        BANKSIZE $1000000
        BANKS 1
    .ENDRO

    .BANK 0 SLOT 0
    .ORG 0
    .ADL ON

    jp start
    AGON_MOS_EXEC_NAME "APP.BIN"

    .ORG AGON_MOS_HEADER_OFFSET
    AGON_MOS_HEADER_ADL

    start:
        ret

`AGON_MOS_HEADER_Z80` emits the same header with the Z80-mode byte. For custom mode selection, use `AGON_MOS_HEADER AGON_MOS_RUNMODE_ADL` or `AGON_MOS_HEADER AGON_MOS_RUNMODE_Z80`.

# 8. Cx4 Notes

WLA Cx4 targets the Capcom Cx4 instruction format used by the Hitachi HG51B169. The backend is usable as a normal WLA target, but control flow deserves a short CPU-specific note because jump, branch, and call operands are page-local.

## 8.1. Program Page Model

Cx4 control flow is split into two parts:

- the opcode operand supplies the low 8 bits of the target program counter

- the current program page stays unchanged unless the instruction uses the far form

In WLA syntax, the far form is written with `.F`. For example:

- `JMP <label` keeps the current program page and loads the low target byte

- `JMP.F <label` loads the low target byte and also transfers the page selector from `P`

- the same rule applies to `BRA`, `BSR`, `JSR`, and the conditional forms

WLA does not infer the page setup from a label. You must manage the page selector explicitly with `MOV P,x`, `LD P,x`, `MOV PH,x`, and `MOV PL,x`.

## 8.2. Labels And Operands

For Cx4 control-flow operands, prefer explicit byte selection with `<label` or `lobyte(label)`.

Example:

    MOV P, >RenderLoop
    JSR.F <RenderLoop

This keeps the intent obvious:

- `>RenderLoop` selects the page byte used to set up `P`

- `<RenderLoop` selects the low 8-bit PC value encoded in the jump or call

Plain label operands such as `JMP RenderLoop` only work when the final label value already fits in one byte. That is a linker-level 8-bit relocation rule in WLA, not a full page-aware Cx4 relocation.

## 8.3. Recommended Pattern

For calls or jumps to code outside the current 256-byte page, keep the page load and the far control-flow instruction next to each other:

    MOV P, >MathInit
    JSR.F <MathInit

For local control flow inside the current page, use the non-far form:

    JSR <LocalHelper
    BRA <LoopTop

## 8.4. Practical Notes

- The Cx4 backend in WLA emits 16-bit instruction words as low byte first, matching the rest of the existing tests.

- The dedicated regression tests under `tests/cx4` cover mnemonic encoding, arithmetic expressions, and linker-style external symbol resolution for page-local targets.

- If you want to keep source readable, use `<label` and `>label` directly instead of baking page and offset constants by hand.

# 9. SH-2 support

WLA DX includes a plain Hitachi SH-2 target named `wla-sh2`. It supports the base SH-2 integer instruction set only. Later SH extensions are outside this target. Sega 32X support is provided as memory maps and include files on top of the plain SH-2 target; see Sega 32X support.

The assembler emits fixed-width 16-bit instructions in big-endian order. General purpose registers are written as `R0` through `R15`. Control and system registers supported by the transfer instructions are `SR`, `GBR`, `VBR`, `MACH`, `MACL` and `PR`.

Addressing syntax follows the SH manuals, including `@Rn`, `@Rn+`, `@-Rn`, `@(disp,Rn)`, `@(R0,Rn)`, `@(disp,GBR)` and `@(disp,PC)`. Displacements are range-checked and scaled according to the instruction size. For PC-relative word and longword loads, labels are resolved by WLAlink and must be aligned for the selected access size.

Branch labels for `bf`, `bt`, `bf/s`, `bt/s`, `bra` and `bsr` are resolved relative to `PC+4`. WLA DX does not currently insert delay-slot instructions automatically, but it does perform some validation and emits warnings for problematic delay-slot contents such as branch, jump and return instructions, so source code must still provide correct delay-slot instructions.

# 10. Sega 32X support

WLA DX provides initial Sega 32X support through reusable memory maps and include files. The 32X is a Mega Drive/Genesis cartridge system with two SH-2 CPUs, so a complete ROM normally has both 68000-side boot/support code and SH-2-side code.

Keep the two CPU families in separate link steps. WLALINK intentionally rejects mixing SH-2 objects with non-SH-2 objects. A 32X project should link the 68000 payload and SH-2 payload separately, then compose the final raw cartridge image from binaries.

## 10.1. Memory maps

`memorymaps/md32x68k.i` is for 68000-side 32X support code. It includes the raw cartridge window, the common Mars 68000 hot-start mirror around `$880000`, 32X framebuffer and palette windows, adapter registers, Z80 RAM, Mega Drive VDP ports, and 68000 work RAM.

`memorymaps/sh232x.i` is for SH-2-side code. It maps raw cartridge file offset 0 to SH-2 address `$02000000`, matching the way MAME exposes the 32X `gamecart_sh2` region. It also includes SDRAM, Mars registers, palette RAM, and framebuffer windows. SH-2 internal registers such as `$FFFFFE92` are provided as constants in `include/sega32x/sh2.inc` rather than as memory-map slots because WLA memory-map slot starts are signed-positive values.

## 10.2. Include files

`include/sega32x/68k.inc` defines the 68000-visible 32X adapter registers at `$A15100` and related constants. It also includes small helper macros for enabling the adapter, emitting a source-built boot jump to the 32X hot-start mirror, toggling FM/32X hardware access, asserting command interrupts to both SH-2s, and setting or clearing the RV bit.

`include/sega32x/sh2.inc` defines SH-2-visible Mars registers, communication ports, PWM registers, 32X VDP registers, framebuffer and palette addresses, SH-2 cache/internal register constants, and simple interrupt-mask helper macros.

`include/sega32x/macros.inc` contains shared video and color constants usable from either side.

## 10.3. ROM layout notes

Standard 32X cartridges use a Mega Drive ROM header at `$100`, a Mars header around `$3C0`, and 68000 bootstrap code at `$3F0`. The Mars header contains the primary and secondary SH-2 entry points and vector-base addresses. Use `.DD` for 32-bit SH-2/Mars header fields; `.DL` is a 24-bit directive.

The `examples/sh2/hello_world_32x` example shows the intended packaging pattern: keep the standard 32X startup blob, the 68000 hot-start support code, and the SH-2 payload in separate steps, then compose the raw cartridge image with `.INCBIN`. The Mars header can point the startup blob at the SH-2 payload in ROM and request that it be copied to SDRAM before the SH-2 CPUs start.

The `examples/sh2/hello_world_32x` makefile launches Ares with the `Mega 32X` system for true SH-2 execution. It auto-detects `~/Downloads/ares-v147/ares.exe` under Cygwin, or you can override the `ARES` variable.

# 11. Bugs

If you find bugs, please let us know about them via GitHub: https://github.com/vhelin/wla-dx/issues

# 12. Files

## 12.1. `tests`

The main purpose of the files in the `tests` directory is to test that WLA and WLALINK can assemble and link the tiny project correctly. You can also take a look at the code and syntax in the files, but beware: if you run the rom files you probably don’t see anything on screen.

`include` directory under `gb-z80` could be very useful as the six include files there have all the Game Boy hardware register address and memory definitions you could ever need and more.

`include/megadrive` contains Sega Mega Drive/Genesis and Sega CD register definitions and helper macros for the 68000 side, Z80 side, VDP, Sega CD main CPU, Sega CD sub CPU, J-Cart and common serial EEPROM wiring.

`include/sega32x` contains Sega 32X register definitions and helper macros for the Mega Drive 68000 side and the 32X SH-2 side. `68k.inc` describes the 68000-visible adapter registers at `$A15100` and friends, `sh2.inc` describes the SH-2-visible Mars registers and SH-2 internal register constants, and `macros.inc` contains shared video/color constants.

`include/pcengine` contains PC Engine / TurboGrafx-16 HuC6280 hardware register definitions, vector constants and small CPU helper macros.

`include/lynx` contains Atari Lynx 65C02 hardware base definitions, vector constants and small CPU helper macros.

`include/agon` contains Agon MOS helper macros for eZ80 binaries, including the standard MOS executable name and header bytes.

## 12.2. `tests/gb-z80/lib`

This folder holds few very useful libraries for you to use in your Game Boy projects. Instead of reinventing the wheel, use the stuff found in here. Remember to compile the libraries right after you’ve installed WLA by executing `make` in the `lib` directory.

## 12.3. `memorymaps`

Here you can find default memory maps (see `.MEMORYMAP`) for various computers and video game consoles.

The Mega Drive/Genesis maps include the normal 68000 and Z80 maps, SSF banking, serial EEPROM cartridges, J-Cart cartridges, lock-on cartridges, and Sega CD main/sub CPU boot program layouts.

The Sega 32X maps include `md32x68k.i` for 68000-side boot/hot-start code and `sh232x.i` for SH-2-side cartridge ROM, SDRAM, Mars registers, palette, and framebuffer windows.

The Agon MOS flat eZ80 map is `agon_mos.i`. The PC Engine map is `pcengine.i`. The Atari Lynx flat 65C02 map is `lynx.i`.

# 13. Functions

WLA supports functions in addition to `.MACRO` s. Functions are different from `.MACRO` s as functions always return a value.

## 13.1. User defined functions

Use `.FUNCTION` to create your own functions.

## 13.2. Built-in functions

The following built-in functions can be used where ever a number is expected:

abs(exp) | Returns the positive version of the argument
acos(exp) | The same as ANSI C90 acos()
asc(exp) | Uses `.ASCIITABLE` to map the supplied value
asin(exp) | The same as ANSI C90 asin()
atan(exp) | The same as ANSI C90 atan()
atan2(exp) | The same as ANSI C90 atan2()
bank() | Returns the current bank (*)
bank(label) | Returns the bank of the supplied label (the same as preceding `:`)
bankbyte() | Returns the current bank byte, bits 16-23 (*)
bankbyte(label) | Returns the bank byte, bits 16-23, of the supplied label
base() | Returns current base (*)
base(label) | Returns the base of the supplied label
blank(s) | Returns 1 (true) if `s` is empty or whitespace, 0 (false) otherwise
ceil(exp) | The same as ANSI C90 ceil()
clamp(value, min, max) | Clamps the value between min and max
cos(exp) | The same as ANSI C90 cos()
cosh(exp) | The same as ANSI C90 cosh()
defined(definition) | Returns 1 (true) if the supplied definition exists, 0 (false) otherwise
definedfunction(func) | Returns 1 (true) if the supplied function exists, 0 (false) otherwise
definedmacro(macro) | Returns 1 (true) if the supplied macro exists, 0 (false) otherwise
exists(path) | Returns 1 (true) if the supplied file exists, 0 (false) otherwise
floor(exp) | The same as ANSI C90 floor()
get(keyword1) | Returns value/string depending on what `keyword1` is
hibyte(exp) | Returns the high byte, bits 8-15 (the same as preceding `>`)
hiword(exp) | Returns the high word, bits 16-31
is(keyword2) | Return 0 (false) or 1 (true), see below for “keyword2”
left(len, s) | Returns the leftmost `len` characters of `s`
lobyte(exp) | Returns the low byte, bits 0-7 (the same as preceding `<`)
log(exp) | The same as ANSI C90 log()
log10(exp) | The same as ANSI C90 log10()
loword(exp) | Returns the low word, bits 0-15
match(a, b) | Returns 1 (true) if `a` and `b` have matching token types
max(exp1, exp2) | Returns the bigger value
mid(ind, len, s) | Returns `len` characters of `s`, starting at index `ind`
min(exp1, exp2) | Returns the smaller value
org() | Returns the current address since the start of the slot (*)
orga() | Returns the current 16-bit memory address (*)
pow(base, power) | The same as ANSI C90 pow()
random(min, max) | Returns a pseudo random integer like `.DBRND` [min, max]
right(len, s) | Returns the rightmost `len` characters of `s`
round(exp) | The same as ANSI C99 round()
sign(exp) | Return 0 if the supplied value is 0, -1 if negative and 1 if positive
sin(exp) | The same as ANSI C90 sin()
sinh(exp) | The same as ANSI C90 sinh()
slot() | Returns the current slot (*)
sqrt(exp) | Returns the square root of the supplied value
substring(s, ind, len) | Returns a substring of `s`, starting at index `ind`, consisting of `len` characters
tan(exp) | The same as ANSI C90 tan()
tanh(exp) | The same as ANSI C90 tanh()
tcount(s) | Returns the number of tokens in `s`
xmatch(a, b) | Returns 1 (true) if `a` and `b` have the same tokens

Note! Use bankbyte() with WLA-65816 as on that platform the bank (+ base) bits are 16-23. On other platforms bank() works better.

Note! Functions marked with (*) are evaluated in the assembler, so if the linker relocates the code then these functions return possibly wrong values.

Note! `match()`, `xmatch()` and `tcount()` operate on WLA token text supplied as strings or expanded macro arguments. `match()` compares token types, while `xmatch()` compares the token text as well.

## 13.3. Examples of functions

Here’s an example about how these functions can be used

    .IF defined(USE_DEBUG) && defined(DEBUG_SHOW) && min(VALUE_A, VALUE_B) > 10

    LDX #lobyte(playMusic)          ; instead of (playMusic & $FF)
    LDA #bank(playMusic)            ; instead of :playMusic
    .DB random(0, 10)               ; defines a byte with value 0-10
    .DL (base() << 16) | orga()     ; defines the current 24-bit address

    .IF blank("")
    .ENDIF

    .IF match("lda #1", "foo #2")
    .ENDIF

    .IF xmatch("lda #1", "lda #1")
    .ENDIF

    .DB tcount("lda #1,foo")
    .DB left(4, "WLA-DX")

    .ENDIF

NOTE: random() needs immediate min and max values.

NOTE: If you use e.g., bank(label) inside an .IF then the current bank for the label is given. If WLALINK e.g., changes the label’s .SECTION’s bank for some reason (e.g., the .SECTION is relocated) then .IF is not calculated correctly.

NOTE: bank(), bankbyte(), base() and slot() without arguments use the information the assembler knows, not the linker.

## 13.4. Keywords

Here are the supported keyword1s for get()

    "section.aligment"              ; returns the current .SECTION's alignment (int)
    "section.name"                  ; returns the current .SECTION's name (string)
    "section.offset"                ; returns the current .SECTION's offset (int)
    "section.priority"              ; returns the current .SECTION's priority (int)
    "section.type"                  ; returns the current .SECTION's type (string),
                                    ;   possible strings being "FREE", "FORCE", "OVERWRITE",
                                    ;   "HEADER", "SEMIFREE", "ABSOLUTE", "SUPERFREE",
                                    ;   "SEMISUBFREE" and "SEMISUPERFREE"
    "label.latest"                  ; returns the latest defined label

Here are the supported keyword2s for is()

    "insidesection"                 ; is the parser at this point inside a .SECTION?

# 14. Temporary Files

Note that WLA will generate temporary files while it works. The files are generated using ANSI C’s tmpfile() function.

When WLA finishes its work these files are deleted as they serve of no further use.

# 15. Compiling

## 15.1. Compiling Object Files

To compile an object file use the `-o [OUT]` option on the command line.

These object files can be linked together (or with library files) later with WLALINK.

Name object files so that they can be recognized as object files. Normal suffix is `.o` (WLA default). This can also be changed with `.OUTNAME`.

With object files you can reduce the amount of compiling when editing small parts of the program. Note also the possibility of using local labels (starting with `_`).

Note: When you compile objects, group 1 directives are saved for linking time, when they are all compared and if they differ, an error message is shown. It is advisable to use something like an include file to hold all the group 1 directives for that particular project and include it to every object file.

If you are interested in the WLA object file format, take a look at the file `txt/wla_file_formats.txt` which is included in the release archive.

Here are some examples of definitions:

- `-D IEXIST`

- `-D DAY=10`

- `-D BASE = $10`

- `-D NAME=elvis`

And here’s an WLA example creating definitions on the command line:

    wla-gb -D DEBUG -D VERBOSE=5 -D NAME = "math v1.0" -o math.o math.s

`DEBUG`’s value will be `0`, `VERBOSE`’s `5` and `NAME` is a string definition with value `math v1.0`. Note that `-D` always needs a space after it, but the rest of the statement can be optionally stuck inside one word.

## 15.2. Compiling Library Files

To compile a library file use the `-l [OUT]` option on the command line.

Name these files so that they can be recognized as library files. Normal suffix is `.lib` (WLA default).

With library files you can reduce the amount of compiling. Library files are meant to hold general functions that can be used in different projects. Note also the possibility of using local labels (starting with `_`). Library files consist only of `FREE` sections.

# 16. Linking

After you have produced one or more object files and perhaps some library files, you might want to link them together to produce a ROM image / program file. WLALINK is the program you use for that. Here’s how you use it:

    wlalink [OPTIONS] <LINK FILE> <OUTPUT FILE>

Choose the option `-b [OUT]` for program file or `-r [OUT]` for ROM image linking. ROM image is all the data in the ROM banks. Program file is the data between the first used byte and the last used byte. You can also use `-bS [START ADDRESS]` and `-bE [END ADDRESS]` to specify the start and the end addresses of the program. Both are optional.

Link file is a text file that contains information about the files you want to link together. Here’s the format:

1. You must define the group for the files. Put the name of the group inside brackets. Valid group definitions are

       [objects]
       [libraries]
       [header]
       [footer]
       [definitions]
       [ramsections]
       [sections]
       [sectionwriteorder]
       [ramsectionwriteorder]

2. Start to list the file names.

       [objects]
       main.o
       vbi.o
       level_01.o
       ...

3. Give parameters to the library files:

       [libraries]
       bank 0 slot 1 speed.lib
       bank 4 slot 2 map_data.lib
       ...

   Here you can also use `base` to define the 65816 CPU bank number (like `.BASE` works in WLA):

       [libraries]
       bank 0 slot 1 base $80 speed.lib
       bank 4 slot 2 base $80 map_data.lib
       ...

   You must tell WLALINK the bank and the slot for the library files.

4. If you want to use header and/or footer in your project, you can type the following:

       [header]
       header.dat
       [footer]
       footer.dat

5. If you have RAMSECTIONs inside the libraries, you must place the sections inside BANKs and SLOTs (ORG and ORGA are optional). Note that you can also change the type and priority of the section, and can use appendto:

       [ramsections]
       bank 0 slot 3 org $0 "library 1 vars 1"
       bank 0 slot 3 orga $6100 priority 100 force "library 1 vars 2"
       bank 0 slot 3 appendto "library 1 vars 2" "library 1 vars 3"

6. If you want to relocate normal sections, do as follows (ORG, ORGA, KEEP, AFTER, OFFSET, PRIORITY, WINDOW, BITWINDOW and APPENDTO are optional, but useful):

       [sections]
       bank 0 slot 1 org $100 appendto "MusicPlayers" "MusicPlayer1"
       bank 0 slot 1 orga $2200 semisubfree priority 100 keep bitwindow 8 "EnemyAI"
       bank 0 slot 2 after "Enemies" offset 256 "Dragon"

7. If you want to make value definitions, here’s your chance:

       [definitions]
       debug 1
       max_str_len 128
       start $150
       ...

8. If you want to change the order in which the linker writes the sections to output:

       [sectionwriteorder]
       OVERWRITE
       FORCE
       FREE
       SEMISUPERFREE
       SEMISUBFREE
       SEMIFREE
       SUPERFREE

9. If you want to change the order in which the linker writes the RAM sections to output:

       [ramsectionwriteorder]
       FREE
       FORCE
       SEMISUBFREE
       SEMIFREE

Note that you have to specify all the section types here.

If flag `v` is used, WLALINK displays information about ROM file after a succesful linking.

If flag `R` is used the file paths inside the link file are relative to the directory where the link file is, not relative to current working directory.

If flag `nS` is used, WLALINK doesn’t sort the sections at all, so they are placed in the output in their order of appearance.

If flag `s` is used, WLALINK will produce a NO$GMB/NO$SNES symbol file. It’s useful when you work under MSDOS (NO$GMB is a very good Game Boy emulator for MSDOS/Windows) as it contains information about the labels in your project.

If flag `S` is used, WLALINK will create a WLA symbol file, that is much like NO$GMB symbol file, but shows also symbols, defines, and breakpoints, not just labels.

If flag `E` is used with a comma- or space-separated list, WLALINK will write debug export files for emulators and tools. Supported formats are `VICE`, `RGBDS` (also `BGB` and `SAMEBOY`), `MESEN`, `EMULICIOUS`, `CSPECT`, `NOCASH`, `MAME` and `JSON`. The `MAME` format writes a MAME debugger command file that can be loaded with MAME’s `source` debugger command.

If flag `sM` is used, WLALINK will produce a MAME-compatible flat symbol file. Each line has the form `AABBCCDD name`, where `AABBCCDD` is the full CPU-visible hexadecimal address of the label. This format is suitable for ingestion by MAME debugger scripts and generic disassembler symbol importers (Ghidra/IDA/etc.).

If flag `d` is used, WLALINK discards all unreferenced `FREE`, `SEMIFREE`, `SEMISUBFREE`, `SUPERFREE` and `RAM` sections. This way you can link big libraries to your project and WLALINK will choose only the used sections, so you won’t be linking any dead code/data.

If flag `D` is used, WLALINK doesn’t create any _sizeof_* labels. Note that to disable fully _sizeof_* label creation, you’ll also need to give WLA the `s` flag.

If flag `pS` is used then WLALINK doesn’t use section type in writing the `.SECTION` s, but instead uses just the `PRIORITY` (and size) when it writes the `.SECTION` s to output.

Flag `pR` works the same as `pS` but for `.RAMSECTION` s.

If flag `t` is used with `c64PRG`, WLALINK will add a two byte header to the program file (use with flag `b`). The header contains the load address for the PRG. Use the flag `a` to specify the load address. It can be a value or the name of a label.

If flag `t` is used with `C64CRT`, WLALINK will write a Commodore 64 CRT cartridge image. Use flag `-64` to specify the cartridge type.

If flag `O` is used with `BIN`, `SMD` or `MD`, WLALINK selects the Mega Drive/Genesis ROM output file format. `BIN` is normal raw output and is also the default when `-O` is omitted, `SMD` writes a 512-byte Super Magic Drive header and per-16KB even/odd interleaving, and `MD` writes all even bytes followed by all odd bytes for the whole ROM image. `SMD` output requires the ROM size to be a multiple of 16KB and is currently limited to 255 16KB blocks (4080KB) for single-file SMD images; `MD` output requires an even ROM size.

If flag `i` is given, WLALINK will write list files. Note that you must compile the object and library files with `-i` flag as well. Otherwise WLALINK has no extra information it needs to build list files. Here is an example of a list file: Let’s assume you’ve compiled a source file called `main.s` using the `i` flag. After you’ve linked the result also with the `i` flag WLALINK has created a list file called `main.lst`. This file contains the source text and the result data the source compiled into. List files are good for debugging. NOTE: list file data can currently be generated only for code inside sections. `.MACRO` calls and `.REPT` s don’t produce list file data either.

If flag `-g` is given, WLALINK also writes list files, but writes one combined list file per object file next to that object file, switching into and out of included files as the source is assembled. This flag implies `-i`.

If flag `L` is given after the above options, WLALINK will use the directory specified after the flag for including libraries. If WLALINK cannot find the library in the specified directory, it will then silently search the current working directory. This is useful when using WLA in an SDK environment where a global path is needed.

Make sure you don’t create duplicate labels in different places in the memory map as they break the linking loop. Duplicate labels are allowed when they overlap each other in the destination machine’s memory. Look at the following example:

    ...
    .BANK 0
    .ORG $150

        ...
        LD      A, 1
        CALL    LOAD_LEVEL
        ...

    LOAD_LEVEL:
        LD      HL, $2000
        LD      (HL), A
        CALL    INIT_LEVEL
        RET

    .BANK 1
    .ORG 0

    INIT_LEVEL:
        ...
        RET

    .BANK 2
    .ORG $0

    INIT_LEVEL:
        ...
        RET
    ...

Here duplicate `INIT_LEVEL` labels are accepted as they both point to the same memory address (in the program’s point of view).

Allow duplicate labels when they have the same values using `C` flag.

If you want to allow for some reason duplicate labels (and definitions) when they have different values, use the `c` flag. The linker will in this case probably use those that it processed first.

Note that when you use .RAMSECTIONs, WLALINK will generate labels RAM_USAGE_SLOT_[slot name/id]_BANK_[bank number]_START and RAM_USAGE_SLOT_[slot name/id]_BANK_[bank number]_END that contain the addresses of the first and last used byte in the RAM bank/slot. Note that this only uses .RAMSECTION information to calculate the addresses, not .ENUMs or anything else.

Examples:

    [seravy@localhost tbp]# wlalink -r linkfile testa.sfc
    [seravy@localhost tbp]# wlalink -d -i -b linkfile testb.sfc
    [seravy@localhost tbp]# wlalink -v -S -L ../../lib linkfile testc.sfc
    [seravy@localhost tbp]# wlalink -v -i -E mame,json linkfile testd.sfc
    [seravy@localhost tbp]# wlalink -v -b -s -t c64PRG -a LOAD_ADDRESS linkfile linked.prg

# 17. Arithmetics

WLA is able to solve really complex calculations like

    -((HELLO / 2) | 3)
    skeletor_end-skeletor
    10/2.5

so you can write something like

    LD HL, data_end-data
    LD A, (pointer + 1)
    CP (TEST + %100) & %10101010

WLALINK also has this ability so it can compute the pending calculations WLA wasn’t able to solve.

NOTE! The assembler has only a limited capability to turn labels into addresses. Often label references are left for the linker to solve. Currently the assembler can do so when the label is outside `.SECTION` s or inside `FORCE` or `OVERWRITE` `.SECTION` s and the label is defined before it is referenced. Many directives like `.ASSERT` require data that the assembler can immediately solve so you might run into problems when feeding labels to directives.

The following operators are valid:

`|` | bitwise or
`&` | bitwise and
`^` | power
`<<` | bitwise shift left
`>>` | bitwise shift right
`+` | plus
`-` | minus
`#` | modulo
`~` | bitwise xor
`*` | multiply
`/` | divide
`<` | get the low byte
`>` | get the high byte
`:` | get the bank byte of an address

Some architectures encode only part of an address in certain operands. For example, Cx4 jump, branch and call targets are page-local 8-bit values, so a cross-page label reference should use `<label` (or `lobyte(label)`) for the encoded operand while page selection is handled separately.

Note that you can do NOT using XOR

    - ``VALUE_A ~ $FF``   is  8-bit NOT
    - ``VALUE_B ~ $FFFF`` is 16-bit NOT

Unary XOR (e.g., `~$FF`) is the same as NOT.

`.IF` conditions have the following additional operators:

`!` | not
`<` | smaller than (note that outside `.IF` this is something else)
`>` | larger than (note that outside `.IF` this is something else)
`<=` | smaller or equal
`>=` | larger or equal
`==` | equal
`!=` | unequal
`||` | logical or
`&&` | logical and

Here’s a table of the precedence of the operators in calculations and conditions (higher priority operators come first):

`(` `)` | expression
`~` `!` | unary
`<` `>` `:` | low byte / high byte / bank (outside `.IF`)
`/` `*` `#` `^` | multiplicative
`+` `-` | additive
`<<` `>>` | bitwise shift
`<` `>` `<=` `>=` | relational (only inside `.IF`)
`==` `!=` | equality (only inside `.IF`)
`&` | bitwise and
`~` | bitwise xor
`|` | bitwise or
`&&` | logical and
`||` | logical or

WLA computes internally with real numbers so `(5/2)*2` produces `5`, not `4`.

# 18. Binary to DB Conversion

WLAB converts binary files to WLA’s byte definition strings. Here’s how you use it:

    wlab -[ap]{bdh} <BIN FILE>

Give it the binary file and WLAB will output the WLA DB formatted data of it into stdout. Here’s an example from real life:

    wlab -da gayskeletor.bin > gayskeletor.s

WLAB has three command flags of which one must be given to WLAB:

`-b`

  Output data in binary format.

`-d`

  Output data in decimal format.

`-h`

  Output data in hexadecimal format.

WLAB has also two option flags:

`-a`

  Print the address (relative to the beginning of the data).

`-p`

  Don’t print file header.

Examples:

    [seravy@localhost src]# wlab -bap iscandar.bin > iscandar.s
    [seravy@localhost src]# wlab -h starsha.bin > starsha.s

# 19. Things you should know about coding for…

Please be aware that the source code files in there are mainly used to test that the compiler and linker work, they are not possibly good examples of how you should write code using WLA DX.

## 19.1. Z80

Check the Z80 specific directives. All SMS/GG coders should find `.SMSTAG`, `.SDSCTAG` and `.COMPUTESMSCHECKSUM` very useful…

There are shadow register aliases for opcodes that use registers A, F, BC, DE and HL. The shadow register versions are just for convenience, if the programmer wants to explicitly show that he is now using the shadow registers. For example:

> AND A ; (original, assembles to 0xA7) AND A’ ; (alias, assembles to 0xA7 and is in reality “AND A”)

Opcodes that make relative label references:

    JR *
    DJNZ

## 19.2. 6502

For example mnemonics `ADC`, `AND`, `ASL`, etc… cause problems to WLA, because they take different sized arguments. Take a look at this:

    LSR 11       ; $46 $0B
    LSR $A000    ; $4E $00 $A0

The first one could also be

    LSR 11       ; $4E $0B $00

To really get what you want, use `.8BIT`, `.16BIT` and `.24BIT` directives. Or even better, supply WLA the size of the argument:

    LSR 11.W     ; $4E $0B $00

Opcodes that make relative label references:

    BCC
    BCS
    BEQ
    BMI
    BNE
    BPL
    BVC
    BVS

## 19.3. 65C02

Read the subsection 6502 as the information applies also to 65C02 coding…

Opcodes that make relative label references:

    BCC
    BCS
    BEQ
    BMI
    BNE
    BPL
    BVC
    BVS
    BRA
    BBR*
    BBS*

## 19.4. 65CE02

Read the subsection 6502 as the information applies also to 65CE02 coding…

Opcodes that make relative label references:

    BCC
    BCS
    BEQ
    BMI
    BNE
    BPL
    BVC
    BVS
    BRA
    BSR
    BBR*
    BBS*

## 19.5. 65816

Read the subsection 6502 as the information applies also to 65816 coding…

WLA-65816 has also few SNES specific directives which are all very helpful. Remember that when you use `.LOROM`, `.HIROM`, `.SLOWROM` and `.FASTROM` WLA automatically writes the information into the output. `.COMPUTESNESCHECKSUM`, `.SNESHEADER` and few others could also be useful.

Use `.BASE` to set the upmost eight bits of 24-bit addresses.

If possible, use operand hints to specify the size of the operand. WLA is able to deduce the accumulator/index mode to some extent from `REP`/`SEP`-mnemonics and `.ACCU` and `.INDEX`-directives, but just to be sure, terminate the operand with `.B`, `.W` or `.L`.

    AND #10    ; can be two different things, depending on the size of the operand.
    AND #10.B  ; forces 8-bit immediate value.
    AND #10.W  ; forces 16-bit immediate value.

    AND 10     ; can be three different things, depending on the size of the operand.
    AND 10.B   ; forces 8-bit address.
    AND 10.W   ; forces 16-bit address.
    AND 10.L   ; forces 24-bit address.

Or if you must, these work as well:

    AND.B #10  ; the same as "AND #10.B".
    AND.W #10  ; the same as "AND #10.W".

    AND.B 10   ; the same as "AND 10.B".
    AND.W 10   ; the same as "AND 10.W".
    AND.L 10   ; the same as "AND 10.L".

Opcodes that make relative label references:

    BCC
    BCS
    BEQ
    BMI
    BNE
    BPL
    BVC
    BVS
    BRA
    BRL
    PER

Use `.WDC` to start parsing WDC standard assembly code. `.NOWDC` sets the parser to parse WLA syntax assembly code.

`MVN` and `MVP` work as follows:

    MVN $xx, $yy
    MVN $xxyy
    MVP $xx, $yy
    MVP $xxyy

`xx` is the source bank, `yy` is the target bank.

## 19.6. MC68000

In addition to operand hints `.B`, `.W` and `.L` we also have `.D` (32-bit).

## 19.7. HUC6280

Read the subsection 6502 as the information applies also to HUC6280 coding…

As PC Engine’s zero page starts at $2000 (imagine `ZEROPAGE1` label’s address is $2001), operand hint `.#b` will be useful:

    STA ZEROPAGE1.#B  ; $85 $01

It takes the lowest 8 bits of `ZEROPAGE1` and hints the assembler’s parser that the operand is 8 bits in size.

Opcodes that make relative label references:

    BCC
    BCS
    BEQ
    BMI
    BNE
    BPL
    BVC
    BVS
    BSR
    BBR*
    BBS*

## 19.8. SPC-700

Note that you’ll have to put an exclamation mark before a 16-bit value. For example,

    CALL !Main
    AND  A, !$1000

Opcodes that make relative label references:

    BCC
    BCS
    BEQ
    BMI
    BNE
    BPL
    BVC
    BVS
    BRA
    BBS
    BBC
    CBNE *
    DBNZ *

## 19.9. Pocket Voice (GB-Z80)

Pocket Voice uses its own MBC. You can enable Pocket Voice mode by selecting Pocket Voice cartridge type (`$BE` in `$0147`) and defining correct `.ROMBANKMAP` and `.MEMORYMAP`. In PV mode bank 0 is 24KB and the rest are 8KB.

Note that WLA assumes that ROM offset is all the time 0. If you use something else as the offset, make sure to compute the jumps by hand as WLA cannot do that.

Check out `tests/gb-z80/include/pocket_voice.i` for more information.

## 19.10. GB-Z80

WLA outputs only `$10` when it decodes `STOP`. Often it’s necessary to put an extra `NOP` (`$00`) after a `STOP`, and sometimes something else, but that’s left entirely to the user.

Opcodes that make relative label references:

    JR *

# 20. WLA Flags

Here are short descriptions for the flags you can give to WLA:

You can supply WLA with some (or all or none) of the following option flags:

    -c  Continue parsing after an error. Currently we can only continue after
        encountering an unknown symbol or a mistyped instruction.
    -d  Disable WLA's ability to calculate A-B where A and B are labels
    -h  Assume that all label references are 16-bit by default (size hints
        still work). Without this flag it's assumed that label references are
        8-bit unless otherwise specified.
    -i  Add list file information. Adds extra information to the output so
        WLALINK can produce list files.
    -k  Keep all empty sections. By default they are discarded.
    -M  WLA generates makefile rules describing the dependencies of the main
        source file.
    -MP Create a phony target for each dependency other than the main file,
        use this with -M.
    -MF Specify a file to write the dependencies to, use this with -M.
    -q  Quiet mode. ``.PRINT*`` -directives output nothing.
    -s  Don't create _sizeof_* and _padding_* definitions.
    -t  Test assemble. Doesn't output any files.
    -v  Verbose mode. Shows a lot of information about the compiling process.
    -v1 Verbose messages (only discard sections)
    -v2 Verbose messages (-v1 plus short summary)
    -w  Require labels to end in a colon.
    -x  Extra compile time labels and definitions. WLA does extra work by creating
        few helpful definitions, and labels SECTIONSTART_[section name] and
        SECTIONEND_[section name] at the beginning and end of a section.
    -D  Declare a definition.

One (and only one) of the following command flags must be defined.

> `-l`

>   Output a library file.

> `-o`

>   Output an object file.

You may also use an extra option to specify the include directory. WLA will search this directory for included files before defaulting to the specified `.INCDIR` or current working directory:

    -I  Directory to include files.

Examples:

    [seravy@localhost tbp]# wla -D VERSION=255 -x -v -i -o testa.o testa.s
    [seravy@localhost tbp]# wla -M testa.s
    [seravy@localhost tbp]# wla -D VERSION=$FF -D MESSAGE=\"Hello world\" -l testb.lib testb.s
    [seravy@localhost tbp]# wla -I ../../include -l testb.lib testb.s
    [seravy@localhost tbp]# wla -M -I myfiles -l testa.lib testa.s

NOTE: If you use -M and -l/-o at the same time, specify -M first on the command line.

NOTE: The first example produces a file named `testa.o`.

# 21. Extra compile time definitions

When you supply WLA with the flag `x` it will maintain few useful definitions and labels while compiling your source codes. Please use the enhanced error reporting engine (so don’t use flag `f`) in conjunction with flag `x` as some of the definitions require extra information about the flow of the data which isn’t available when using the old, crippled error reporting engine.

Here’s a list of definitions you get when you use flag `x`:

`WLA_FILENAME` | A string definition holding the file name WLA is currently processing.
`WLA_TIME` | A string definition holding the calendar time (obtained using C’s `ctime()`).
`WLA_VERSION` | A string definition holding the version number of WLA.

So you can do for example something like

    .DB WLA_TIME

to store the time when the build process started into the ROM file you are compiling.

Definition `CADDR`, which is present without supplying the flag `x`, contains the current 16-bit memory address. So

    LD HL, CADDR

will load the address of the operand data into registers `H` and `L`.

CAVEAT: Remember when using defines that contain `CADDR` gets the address of the place where the definition is used, not the address of the definition, which contains the `CADDR`.

Note that you’ll also get all these definitions in lower case (e.g., `wla_filename`).

But that is not all. You will also get SECTIONSTART_[section name] labels that are inserted into the start of every section, and SECTIONEND_[section name] labels that are inserted into the end of every section.

# 22. Good things to know about WLA

- Is 511 (Amiga, MSDOS) or 2047 (other platforms) bytes too little for a string (file names, labels, definition labels, etc)? Check out `MAX_NAME_LENGTH` in `shared.h`.

- Want to have more operators and operands in a calculation than 64 (Amiga, MSDOS) or 256 (other platforms)? Check out `MAX_STACK_CALCULATOR_ITEMS` in `defines.h`.

- WLA preprocessor doesn’t expand macros and repetitions. Those are actually traversed in the assembling phase.

- WLA’s source code is mainly a huge mess, but WLALINK is quite well structured and written. So beware!

- To get the length of a string e.g. “peasoup”, write “peasoup”.length.

- Do not write `.E` into your sources as WLA uses it internally to mark the end of a file.

# 23. WLA DX’s architectural overview

The two most important executables inside WLA DX are WLA (the assembler) and WLALINK (the linker).

## 23.1. WLA

WLA has four separate phases:

1. `phase_1.c`: `phase_1()`:

   - The biggest data processor in WLA.

   - Includes the include files: every time this happens the file is read in, white space is removed, lines formatted, etc.

   - Macros are processed along with directives

   - All textual data, code, etc. are transformed into WLA’s internal byte code that gets written into a tmp (TMP) file, and after this phase the assembler or the linker has no idea of target CPU’s opcodes - all is just pure WLA byte code.

   - The first and the only pass that handles the assembly source files supplied by the user.

   - The parser in this pass starts from the first byte of the first source file, then moves forward parsing everything that it encounters, but when a macro is called, the parser jumps to the beginning of the macro, and continues parsing from there.

2. `phase_2.c`: `phase_2()`:

   - If the user has issued directives like `.SDSCTAG`, here we generate the needed data and write that into TMP.

3. `phase_3.c`: `phase_3()`:

   - Here we read in TMP and do some sanity checks for the data, give labels addresses (if possible), generate internal structures for labels and sections.

4. `phase_4.c`: `phase_4()`:

   - Again we read in TMP.

   - Now we check that if there is a reference to a calculation, and that calculation has been succesfully calculated, then we can replace the reference with the result.

   - This phase writes out object and library files, i.e., transforms TMP to final output files (this write out could actually be `pass_5`)…

## 23.2. WLALINK

WLALINK is much simpler and more straight forward than WLA; WLALINK just reads in all the objects and library files, places the sections along with labels into the target memory map, solves pending calculations, calculates checksums, and writes out the final ROM/PRG files. `wlalink/main.c:main()` should quite clearly display all the higher level phases in the linking process.

# 24. WLA Symbols

Symbols can be optionally generated as a part of the assembly and link steps. With a compatible emulator, this can provide extra information for debugging a ROM, or otherwise help in understanding how it operates.

The symbols file can be generated by wlalink by adding “-S” onto the command line. This will output labels, definitions, and some other rudimentary data. Most prominently, this can be used to understand where the ROM output various sections such as subroutines and data, and be able to look that up in the emulator’s ROM or RAM space.

Extra information for address-to-line mapping can be provided by adding the following command line arguments: - Run object generation (e.g. “wla-65816”) with “-i” to include list data in the output obj files - Run wlalink with “-S -A” to generate symbols with information related to address-to-line mapping

Address-to-line mappings includes information to relate lines in the source files to individual instructions in the generated ROM. This can be used to provide richer disassembly in the emulator, or allow for rich debugging in an external IDE.

## 24.1. WLA Symbol Version History

If you are maintaining a WLA symbol file parser, please review this page when new versions of WLA DX are released, as the format might have changed.

Version 1: https://github.com/vhelin/wla-dx/blob/v9.12/doc/symbols.rst

- Base version, including sections [labels], [definitions], [breakpoints], [symbols], [source files], [rom checksum], [addr-to-line mapping]

Version 2: https://github.com/vhelin/wla-dx/blob/v10.5/doc/symbols.rst

- Added [information] section

- Deprecated [source files] section, and replaced with [source files v2]

- Deprecated [addr-to-line mapping] section definition, and replaced with [addr-to-line mapping v2]

Version 3: https://github.com/vhelin/wla-dx/blob/master/doc/symbols.rst

- Added [sections] and [ramsections] sections

- Added “wlasymbol true” under [information] section

## 24.2. Information For Emulator Developers

In order to properly support loading of WLA symbol files, it is recommended to follow this specification below, especially so as to gracefully support future additions to the symbol files.

- The file should be read one line at a time

- Any text on a line following a `;` should be ignored

- Lines matching `\[\S+\]` in regex or `[%s]` in scanf code are section headers, and represent a new section. Note that no section data will start with `[`.

- Lines following the section header are the data for that section. If you’re acknowledging the section, utilize that section’s specific formatting. Read lines that match until a new section header is encountered.

- Unless otherwise specified, none of the data in any section should be assumed to be sorted in any particular way.

The following are the list of currently supported sections, what they mean, and how their data should be interpreted.

### 24.2.1. [information]

The only fields this section has currently are “version” (and then the version number) and “wlasymbol” (which is followed by “true”). [information], if present, must always occur before any other section or data, and its first line will always be the format version.

### 24.2.2. [labels]

This is a list of all labels to sections of the ROM, such as subroutine locations, or data locations. Each line lists an address in hexadecimal (bank and offset) and a string associated with that address. This data could be used, for example, to identify what section a given target address is in, by searching for the label with the closest address less than the target address.

- Regex match: `[0-9a-fA-F]{2}:[0-9a-fA-F]{4} .*`

- Format specifier: `%2x:%4x %s`

### 24.2.3. [definitions]

This is a list of various definitions provided in code - or automatically during WLA’s processing - and values associated with them. Most prominently, WLA outputs the size of each section of the ROM. Each line lists an integer value in hexadecimal, and a string (name) associated with that value.

- Regex match: `[0-9a-fA-F]{8} .*`

- Format specifier: `%8x %s`

### 24.2.4. [breakpoints]

This is a list of hexadecimal ROM addresses where the `.BREAKPOINT` directive was used in the source assembly. Each line lists an address in hexadecimal (bank and offset).

- Regex match: `[0-9a-fA-F]{2}:[0-9a-fA-F]{4}`

- Format specificer: `%2x:%4x`

### 24.2.5. [symbols]

This is a list of hexadecimal ROM addresses where the `.SYMBOL` directive was used in the source assembly. Each line lists an address in hexadecimal (bank and offset) and a string associated with that address.

- Regex match: `[0-9a-fA-F]{2}:[0-9a-fA-F]{4} .*`

- Format specifier: `%2x:%4x %s`

### 24.2.6. [source files v2]

These are used to identify what files were used during the assembly process, especially to map generated assembly back to source file contents. Each line lists a hexadecimal object file index, a hexadecimal source file index, a hexadecimal CRC32 checksum of the file, and a file path relative to the generated ROM’s root. This could be used to load in the contents of one of the input files when running the ROM and verifying the file is up-to-date by checking its CRC32 checksum against the one generated during assembly.

- Regex match: `[0-9a-fA-F]{4}:[0-9a-fA-F]{4} [0-9a-fA-F]{8} .*`

- Format specifier: `%4x:%4x %8x %s`

### 24.2.7. [rom checksum]

This is just a single line identifying what the hexadecimal CRC32 checksum of the ROM file was when the symbol file was generated. This could be used to verify that the symbol file itself is up-to-date with the ROM in question. This checksum is calculated by reading the ROM file’s entire binary, and not by reading any platform-specific checksum value embedded in the ROM itself.

- Regex match: `[0-9a-fA-F]{8}`

- Format specifier: `%8x`

### 24.2.8. [addr-to-line mapping v2]

This is a listing of hexadecimal ROM address, bank, ROM bank offset, memory address, each mapped to a hexadecimal object file index, a source file index and hexadecimal line index. The file indices refer back to the file indices specified in the `source files` section, so that the source file name can be discovered. This information can be used to, for example, display source file information in line with disassembled code, or to communicate with an external text editor the location of the current Program Counter by specifying a source file and line instead of some address in the binary ROM file.

- Regex match: `[0-9a-fA-F]{8} [0-9a-fA-F]{2}:[0-9a-fA-F]{4} [0-9a-fA-F]{4} [0-9a-fA-F]{4}:[0-9a-fA-F]{4}:[0-9a-fA-F]{8}`

- Format specifier: `%8x %2x:%4x %4x %4x:%4x:%8x`

### 24.2.9. [sections]

Each line specifies a `.SECTION`: hexadecimal ROM address, bank, ROM bank offset, memory address, size and name. Use this information for example to locate `.SECTION` data in the output.

- Regex match: `[0-9a-fA-F]{8} [0-9a-fA-F]{2}:[0-9a-fA-F]{4} [0-9a-fA-F]{4} [0-9a-fA-F]{8} .*`

- Format specifier: `%.8x %.2x:%.4x %.4x %.8x %s`

### 24.2.10. [ramsections]

Each line specifies a `.RAMSECTION`: hexadecimal bank, RAM bank offset, memory address, size and name. Use this information for example to see where a `.RAMSECTION` was placed.

- Regex match: `[0-9a-fA-F]{2}:[0-9a-fA-F]{4} [0-9a-fA-F]{4} [0-9a-fA-F]{8} .*`

- Format specifier: `%.2x:%.4x %.4x %.8x %s`

# 25. Legal Note

WLA DX (the whole package) was originally written by Ville Helin in 1998-2008. After that everybody has been able to take part in the development of WLA DX, and recently via GitHub. The authors are not responsible for anything the software does.

WLA DX is GPL-2.0-or-later software. For more information about GPL-2.0-or-later, take a look at the `LICENCE` file, or visit https://spdx.org/licenses/GPL-2.0-or-later.html

Game Boy and Game Boy Color are copyrighted by Nintendo.

Pocket Voice is copyrighted by Bung HK.

# 1. Manpage: WLA-LINK

## 1.1. SYNOPSIS

`wlalink` [`OPTIONS`] `LINK_FILE` `OUTPUT_FILE`

## 1.2. OPTIONS

`-b`

  Program file output

`-d`

  Discard unreferenced sections

`-g`

  Write one combined list file per object file (implies `-i`)

`-i`

  Write list files (Note: WLA needs `-i` as wel)

`-r`

  ROM file output (default)

`-s`

  Write also a NO$GMB/NO$SNES symbol file

`-S`

  Write also a WLA symbol file

`-A`

  Add address-to-line mapping data to WLA symbol file

`-E LIST`

  Write debug exports. Supported formats: VICE, RGBDS, MESEN, EMULICIOUS, CSPECT, NOCASH, MAME and JSON

`-v`

  Verbose messages

`-L LIBDIR`

  Look in LIBDIR for libaries before looking in CWD

`-t TYPE`

  Output type (supported types: ‘CBMPRG’, ‘C64CRT’)

-64 TYPE Cartridge type for C64CRT output

`-a ADDR`

  Load address for CBM PRG

Choose one:

`-b OUT`

  Program file linking

`-r OUT`

  ROM image linking

## 1.3. DESCRIPTION

wlalink(1) is a part of WLA-DX. It links one or more object files (and perhaps some library files) together to produce a ROM image / program file.

LINK_FILE is a text file that contains information about the files you want to link together. Here’s the format:

1. You must define the group for the files. Put the name of the group inside brackets. Valid group definitions are

       [objects]
       [libraries]
       [header]
       [footer]
       [definitions]

2. Start to list the file names.

       [objects]
       main.o
       vbi.o
       level_01.o
       ...

3. Give parameters to the library files:

       [libraries]
       bank 0 slot 1 speed.lib
       bank 4 slot 2 map_data.lib
       ...

   Here you can also use `base` to define the 65816 CPU bank number (like `.BASE` works in WLA):

       [libraries]
       bank 0 slot 1 base $80 speed.lib
       bank 4 slot 2 base $80 map_data.lib
       ...

   You must tell WLALINK the bank and the slot for the library files.

4. If you want to use header and/or footer in your project, you can type the following:

       [header]
       header.dat
       [footer]
       footer.dat

5. If you want to make value definitions, here’s your chance:

       [definitions]
       debug 1
       max_str_len 128
       start $150
       ...

If flag `-i` is given, wlalink(1) will write list files. Note that you must compile the object and library files with `-i` flag as well. Otherwise wlalink(1) has no extra information it needs to build list files.

If flag `-g` is given, one combined list file is written per object file next to that object file, with included files shown at the point where they are included. This flag implies `-i`.

The `-E` option writes debug exports for emulators and tools. The format list can be comma- or space-separated. The `MAME` format writes a debugger command file that can be loaded with MAME’s `source` debugger command.

The `-64` option selects the cartridge type when linking `-t C64CRT` output.

Here is an example of a list file: Let’s assume you’ve compiled a source file called `main.s` using the `-i` flag. After you’ve linked the result also with the `-i` flag wlalink(1) has created a list file called `main.lst`. This file contains the source text and the result data the source compiled into. List files are good for debugging.

Make sure you don’t create duplicate labels in different places in the memory map as they break the linking loop. Duplicate labels are allowed when they overlap each other in the destination machine’s memory.

## 1.4. EXAMPLES

    wlalink -r linkfile testa.sfc
    wlalink -d -i -b linkfile testb.sfc
    wlalink -v -S -L ../../lib linkfile testc.sfc
    wlalink -v -i -E mame,json linkfile testd.sfc

# 2. Manpage: WLA-CPU

## 2.1. SYNOPSIS

`wla-6502` [`OPTIONS`] `SRC_FILE`
`wla-65816` [`OPTIONS`] `SRC_FILE`
`wla-65c02` [`OPTIONS`] `SRC_FILE`
`wla-65ce02` [`OPTIONS`] `SRC_FILE`
`wla-cx4` [`OPTIONS`] `SRC_FILE`
`wla-6800` [`OPTIONS`] `SRC_FILE`
`wla-6801` [`OPTIONS`] `SRC_FILE`
`wla-6809` [`OPTIONS`] `SRC_FILE`
`wla-68000` [`OPTIONS`] `SRC_FILE`
`wla-8008` [`OPTIONS`] `SRC_FILE`
`wla-8080` [`OPTIONS`] `SRC_FILE`
`wla-gb` [`OPTIONS`] `SRC_FILE`
`wla-huc6280` [`OPTIONS`] `SRC_FILE`
`wla-spc700` [`OPTIONS`] `SRC_FILE`
`wla-superfx` [`OPTIONS`] `SRC_FILE`
`wla-z80` [`OPTIONS`] `SRC_FILE`
`wla-z80n` [`OPTIONS`] `SRC_FILE`

## 2.2. OPTIONS

`-h`

  Assume all label references are 16-bit by default (size hints still work)

`-i`

  Add list file information

`-k`

  Keep empty sections

`-M`

  Output makefile rules

`-q`

  Quiet mode (`.PRINT*`-directives output nothing)

`-s`

  Don’t create _sizeof_* definitions

`-t`

  Test compile (Don’t output any files)

`-v`

  Verbose messages

`-x`

  Extra compile time labels and definitions

`-I DIR`

  Add include directory

`-D DEF`

  Declare definition

Choose one:

`-o OUT`

  Output an object file

`-l OUT`

  Output an library file

## 2.3. DESCRIPTION

Assemble a BIN_FILE to an object file (`-o`) or to an library file (`-l`).

These object files can be linked together (or with library files) later with wlalink(1).

Name object files so that they can be recognized as object files. Normal suffix is `.o` (WLA default). This can also be changed with `.OUTNAME`.

Name these files so that they can be recognized as library files. Normal suffix is `.lib` (WLA default).

With object files you can reduce the amount of compiling when editing small parts of the program. Note also the possibility of using local labels (starting with `_`).

With library files you can reduce the amount of compiling. Library files are meant to hold general functions that can be used in different projects. Note also the possibility of using local labels (starting with `_`). Library files consist only of `FREE` sections.

Note: When you compile objects, group 1 directives are saved for linking time, when they are all compared and if they differ, an error message is shown. It is advisable to use something like an include file to hold all the group 1 directives for that particular project and include it to every object file.

If you are interested in the WLA object file format, take a look at the file `txt/wla_file_formats.txt` which is included in the release archive.

## 2.4. EXAMPLES

    wla-gb -D DEBUG -D VERBOSE=5 -D NAME = "math v1.0" -o math.o math.s

- `-D IEXIST`

- `-D DAY=10`

- `-D BASE = $10`

- `-D NAME=elvis`

# 3. Manpage: WLAB

## 3.1. SYNOPSIS

`wlab` -[`ap`]{`bdh`} `BIN_FILE`

## 3.2. OPTIONS

`-a`

  Print the address (relative to the beginning of the data).

`-p`

  Don’t print file header.

Choose one:

`-b`

  Output data in binary format.

`-d`

  Output data in decimal format.

`-h`

  Output data in hexadecimal format.

## 3.3. DESCRIPTION

wlab(1) converts binary files to WLA’s byte definition strings and print it to the standard output.

## 3.4. EXAMPLES

    wlab -da gayskeletor.bin > gayskeletor.s
    wlab -bap iscandar.bin > iscandar.s
    wlab -h starsha.bin > starsha.s