dolphin/Source/Core/Common/Src/x64ABI.h

// Copyright 2013 Dolphin Emulator Project
// Licensed under GPLv2
// Refer to the license.txt file included.

#ifndef _JIT_ABI_H_
#define _JIT_ABI_H_

#include "Common.h"

// x86/x64 ABI:s, and helpers to help follow them when JIT-ing code.
// All convensions return values in EAX (+ possibly EDX).

// Linux 32-bit, Windows 32-bit (cdecl, System V):
// * Caller pushes left to right
// * Caller fixes stack after call
// * function subtract from stack for local storage only.
// Scratch:      EAX ECX EDX
// Callee-save:  EBX ESI EDI EBP
// Parameters:   -

// Windows 64-bit
// * 4-reg "fastcall" variant, very new-skool stack handling
// * Callee moves stack pointer, to make room for shadow regs for the biggest function _it itself calls_
// * Parameters passed in RCX, RDX, ... further parameters are MOVed into the allocated stack space.
// Scratch:      RAX RCX RDX R8 R9 R10 R11
// Callee-save:  RBX RSI RDI RBP R12 R13 R14 R15
// Parameters:   RCX RDX R8 R9, further MOV-ed

// Linux 64-bit
// * 6-reg "fastcall" variant, old skool stack handling (parameters are pushed)
// Scratch:      RAX RCX RDX RSI RDI R8 R9 R10 R11
// Callee-save:  RBX RBP R12 R13 R14 R15
// Parameters:   RDI RSI RDX RCX R8 R9

#ifdef _M_IX86 // 32 bit calling convention, shared by all

// 32-bit don't pass parameters in regs, but these are convenient to have anyway when we have to
// choose regs to put stuff in.
#define ABI_PARAM1 RCX
#define ABI_PARAM2 RDX

// There are no ABI_PARAM* here, since args are pushed.
// 32-bit bog standard cdecl, shared between linux and windows
// MacOSX 32-bit is same as System V with a few exceptions that we probably don't care much about.

#else // 64 bit calling convention

#ifdef _WIN32 // 64-bit Windows - the really exotic calling convention 

#define ABI_PARAM1 RCX
#define ABI_PARAM2 RDX
#define ABI_PARAM3 R8
#define ABI_PARAM4 R9

#else  //64-bit Unix (hopefully MacOSX too) 

#define ABI_PARAM1 RDI
#define ABI_PARAM2 RSI
#define ABI_PARAM3 RDX
#define ABI_PARAM4 RCX
#define ABI_PARAM5 R8
#define ABI_PARAM6 R9

#endif // WIN32

#endif // X86

#endif  // _JIT_ABI_H_