hornc / psx-asm-cargo Goto Github PK

Write up this conversion process in a readme, explain some of the more complicated conversions.

Compare the original Greentro release EXE with this generated EXE,

0x80010000
vs
0x80100000 with decrunch (not included in the official source release)

Confirming only psexe.ld is required from Rust psx:

cd hit-greensrc
clang --target=mipsel-sony-psx -c intro.asm
ld.lld -o intro.exe -T psexe.ld --oformat=binary intro.o


mednafen intro.exe

Convert the classic 1998 Greentro asm intro from spASM into the form that compiles with this toolchain.

I've made the conversion and know what's involved, but it's a bit messy. I'd like to show how to convert step-by-step.

Method:

• Copy original source files
• rename (downcase), update inc names and paths
• dos2unix source files
• strip EOL whitespace
• change comment notation
• hex notation, $ff -> 0xff
• register notation s0 -> $s0
• translate labels
• translate directives
• convert subiu pseudo ops to addiu -
• list.inc 24 bit addr + 8 bit size conversion
• switch bnez odering where it has a detrimental effect (remove extra nops after jumps?) Better sol.n: use compiler directive .set noreorder and keep the original delay slot instructions and nops.

I think that's everything.

Bonus:
NTSC compile option? I'm having trouble using Mednafen with NTSC modes -- the vsync is busted on all examples I make and try, and I can't see any config setting to fix the issue. I thought it might have been something else which needs changing in the asm, but now I'm beginning to suspect the emulator.