want to port JIT to MIPS - which calling convention is used here?

https://lists.webkit.org/pipermail/webkit-dev/2009-February/006845.html

want to port JIT to MIPS - which calling convention is used here?

in JITPropertyAccess.cpp:
    if (transitionWillNeedStorageRealloc(oldStructure, newStructure)) {
        pop(X86::ebx);      ///pop return address, why? for exception?
#if PLATFORM(X86_64)        ///which convention is this?
        move(Imm32(newStructure->propertyStorageCapacity()), regT1);  //edx
        move(Imm32(oldStructure->propertyStorageCapacity()), X86::esi);
        move(regT0, X86::edi);
        callTarget = call();
#else                       ///__cdecl, yet how can I know resizePropertyStorage() use __cdecl? 
        push(Imm32(newStructure->propertyStorageCapacity()));
        push(Imm32(oldStructure->propertyStorageCapacity()));
        push(regT0);
        callTarget = call();
        addPtr(Imm32(3 * sizeof(void*)), X86::esp); ///clean stack
#endif