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SCHG How-to

Convert the Hivebrain 2005 disassembly to ASM68K

From Sonic Retro

Revision as of 10:17, 16 March 2010 by Selbi (talk | contribs)

(Original guide by Puto)

This guide covers converting your split disassembly from SNASM68K (the assembler) to a better, faster assembler known as ASM68K. This tutorial is also necesary if you want to work on a 64-bit OS without restarting on a new split.

The only thing that SNASM68K has that ASM68K doesn't seem to support, is the "align" directive, as well as negative cnops. The align issue can be fixed with a simple macro that can be placed above StartOfRom: <asm>align macro

    cnop 0,\1
    endm</asm>

Next edit the line below in build.bat:

snasm68k.exe -emax 0 -p -o ae- s1comb.asm, s1built.bin

With this:

asm68k /o op+ /o os+ /o ow+ /o oz+ /o oaq+ /o osq+ /o omq+ /p /o ae- s1comb.asm, s1built.bin

And then in the source file itself replaced this incorrect line in SkipSecurity: <asm> move a6,usp  ; set usp to $0</asm> With the proper: <asm> move.l a6,usp  ; set usp to $0</asm> Which results in a perfectly assembling rom, which assembles so quickly I can barely have time to see the window open.

Better yet, since this supports long filenames, I can then replace the include.exe directives (in the format of ; include=xxx) with proper "include" directives, which allows me to completely skip the creation of s1comb.asm! This is very useful, because it means when you get a compiling error, you'll no longer have to check the line in s1comb.asm, and then track the location to sonic1.asm.

In the source file, replace all instances of: <asm>; include=</asm> With the proper: <asm> include "</asm>

Ensure that you replace all instances of: <asm>.asm</asm> With: <asm>.asm"</asm>

As such, this entire line becomes unneeded in build.bat:

include.exe sonic1.asm s1comb.asm

And the asm68k line can be changed to assemble sonic1.asm directly.

That's it! Enjoy a faster build of your hack.