Mips calling convention review

Hi! Long days have passed since the last time I wrote here. A Chinese bot stole my domain, and since I havent paid in time, I also lost my old blog stuff. ok, beginning all over again! 😉

I got back to mips llvm work and I’m improving it now to support the psp allegrex core. I improved a lot of minor codegen stuff this month and my next milestone is getting llvm-gcc cross-compiled for Mips, it is breaking now for float stuff, so here we go…

LLVM mips backend currently does only support 32 bit integer arguments (64-bit integer args are not legal and are expanded since 64bit ISAs aren’t supported yet).

I’m currently hacking out the ABI requirements for:

  • Float-point arguments
  • Struct arguments (reference and By Value)
  • Struct returning

Since GCC implementation differs a little from SysV ABI specs (the spec is very bad written) I often get confused if I’m implementing the right thing. To avoid reading this stuff every time I may post some low level info here, so it should be easy to get a reference when needed.

Stay tuned! 😉

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