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Sammi-Husky / Syriinge

Experimental project for runtime hooking Wii games with C++
MIT License
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r0 gets clobbered on InlineHook #2

Open WispSSBM opened 3 months ago

WispSSBM commented 3 months ago

Currently the default inline hook shim process seems to be:

1) Original instruction 2) move LR into R0 3) store LR and r3-31 to a stack frame as usual 4) jump 5) steps 2 & 3 in reverse.

However, this pattern means that if we hook an instruction (or series of instructions) that is using r0, we won't save that value. I think ideally we would also put the original r0 value into the stack frame that we are generating. I think the added safety is likely worth the 4 bytes, but I'd be interested to hear your take on this.

Sammi-Husky commented 3 months ago

Will be fixed in the next version. Although this does bring up some deeper questions about the way we are doing hooks. I am going to revisit the hooking system soon and see if there is any room for optimization.