shaigem / geckon

Simple framework for generating ASM PPC Gecko codes

geckon

A simple build framework for creating ASM Gecko codes in Nim.

Note: geckon is still in development. The APIs for creating codes are subject to change.

Usage

Please see the melee folder for examples of real Gecko codes written for Super Smash Bros. Melee.

Simple Example

import geckon

defineCodes:
    createCode "My New Code Name":
        authors "Bob"
        description "Does cool things"

        patchWrite32Bits "802724A4":
            nop # replaces the single code line at 802724A4 with 'nop'
        
        patchInsertAsm "802724A8":
            # branch to the address 80380580
            lis r12, {0x80380580} @h
            ori r12, r12, {0x80380580} @l
            mtctr r12
            bctrl
            # or you can call branchLink() from geckon/common.nim:
            %branchLink($0x80380580)

build:
    # can specify as many codes as you want
    addCodes Codes
    # by default, all generated .asm and .o files are kept in a folder called 'generated'
    # can specify `keepObjFiles = false` to remove all .o files and keep only .asm files
    output:
        writeCodesToFile "./codes.txt"

Running the script above produces the following gecko code in a file called codes.txt:

$My New Code Name [Bob]
*Does cool things
042724A4 60000000
C22724A8 00000005
3D808038 618C0580
7D8903A6 4E800421
3D808038 618C0580
7D8903A6 4E800421
60000000 00000000

It also generates the following ASM code for reference:

# 802724A4
nop

# 802724A8
lis r12, 2151155072 @h
ori r12, r12, 2151155072 @l
mtctr r12
bctrl
lis r12, 2151155072 @h
ori r12, r12, 2151155072 @l
mtctr r12
bctrl

License

MIT