avcall-x86_64.c

c++写的一个脚本解释器

#ifndef _avcall_x86_64_c				/*-*- C -*-*/
#define _avcall_x86_64_c
/**
  Copyright 1993 Bill Triggs, <[e-mail]>
  Copyright 1995-1999, 2004 Bruno Haible, <[e-mail]>

  This is free software distributed under the GNU General Public
  Licence described in the file COPYING. Contact the author if
  you don't have this or can't live with it. There is ABSOLUTELY
  NO WARRANTY, explicit or implied, on this software.
**/
/*----------------------------------------------------------------------
  !!! THIS ROUTINE MUST BE COMPILED gcc -O -fno-omit-frame-pointer !!!

  Foreign function interface for a Linux x86_64 (a.k.a. amd64) with gcc.

  This calls a C function with an argument list built up using macros
  defined in av_call.h.

  x86_64 Argument Passing Conventions are documented in
  http://www.x86-64.org/abi.pdf.

  Up to six words are passed in integer registers (%rdi, %rsi, %rdx, %rcx,
  %r8, %r9). Up to 8 float/double arguments are passed in SSE registers
  (%xmm0..%xmm7). Varargs functions expect an upper bound for the number
  of SSE register arguments in %al (in the range 0..8). All arguments
  are passed on the stack with word alignment. Structure args are passed
  as true structures embedded in the argument stack. 

  Integers are returned in %rax, %rdx. Float/double values are returned
  in %xmm0, %xmm1. To return a structure, the called function copies the
  value to space pointed to by its first argument, and all other arguments
  are shifted down by one.
  ----------------------------------------------------------------------*/
#include "avcall.h.in"

#define RETURN(TYPE,VAL)	(*(TYPE*)l->raddr = (TYPE)(VAL))

register __avword iarg1 __asm__("rdi");
register __avword iarg2 __asm__("rsi");
register __avword iarg3 __asm__("rdx");
register __avword iarg4 __asm__("rcx");
register __avword iarg5 __asm__("r8");
register __avword iarg6 __asm__("r9");

register double farg1 __asm__("xmm0");
register double farg2 __asm__("xmm1");
register double farg3 __asm__("xmm2");
register double farg4 __asm__("xmm3");
register double farg5 __asm__("xmm4");
register double farg6 __asm__("xmm5");
register double farg7 __asm__("xmm6");
register double farg8 __asm__("xmm7");

int
__builtin_avcall(av_alist* l)
{
  register __avword*	sp	__asm__("rsp");	/* C names for registers */
  register __avword	iret	__asm__("rax");
  register __avword	iret2	__asm__("rdx");
  register double	dret	__asm__("xmm0");

  __avword* argframe = (sp -= __AV_ALIST_WORDS); /* make room for argument list */
  int arglen = l->aptr - l->args;
  int farglen = l->faptr - l->fargs;
  __avword i, i2;

  for (i = 0; i < arglen; i++)		/* push function args onto stack */
    argframe[i] = l->args[i];

  /* put 6 integer args into registers */
  iarg1 = l->iargs[0];
  iarg2 = l->iargs[1];
  iarg3 = l->iargs[2];
  iarg4 = l->iargs[3];
  iarg5 = l->iargs[4];
  iarg6 = l->iargs[5];

  /* Call function.  It's OK to pass 8 values in SSE registers even if the
     called function takes less than 8 float/double arguments. Similarly
     for the integer arguments. */
  if (l->rtype == __AVfloat) {
    *(float*)l->raddr =
      (*(float(*)())l->func)(farglen > 0 ? l->fargs[0] : 0.0,
                             farglen > 1 ? l->fargs[1] : 0.0,
                             farglen > 2 ? l->fargs[2] : 0.0,
                             farglen > 3 ? l->fargs[3] : 0.0,
                             farglen > 4 ? l->fargs[4] : 0.0,
                             farglen > 5 ? l->fargs[5] : 0.0,
                             farglen > 6 ? l->fargs[6] : 0.0,
                             farglen > 7 ? l->fargs[7] : 0.0);
  } else
  if (l->rtype == __AVdouble) {
    *(double*)l->raddr =
      (*(double(*)())l->func)(farglen > 0 ? l->fargs[0] : 0.0,
                              farglen > 1 ? l->fargs[1] : 0.0,
                              farglen > 2 ? l->fargs[2] : 0.0,
                              farglen > 3 ? l->fargs[3] : 0.0,
                              farglen > 4 ? l->fargs[4] : 0.0,
                              farglen > 5 ? l->fargs[5] : 0.0,
                              farglen > 6 ? l->fargs[6] : 0.0,
                              farglen > 7 ? l->fargs[7] : 0.0);
  } else {
    i = (*l->func)(farglen > 0 ? l->fargs[0] : 0.0,
                   farglen > 1 ? l->fargs[1] : 0.0,
                   farglen > 2 ? l->fargs[2] : 0.0,
                   farglen > 3 ? l->fargs[3] : 0.0,
                   farglen > 4 ? l->fargs[4] : 0.0,
                   farglen > 5 ? l->fargs[5] : 0.0,
                   farglen > 6 ? l->fargs[6] : 0.0,
                   farglen > 7 ? l->fargs[7] : 0.0);
    i2 = iret2;

    /* save return value */
    if (l->rtype == __AVvoid) {
    } else
    if (l->rtype == __AVword) {
      RETURN(__avword, i);
    } else
    if (l->rtype == __AVchar) {
      RETURN(char, i);
    } else
    if (l->rtype == __AVschar) {
      RETURN(signed char, i);
    } else
    if (l->rtype == __AVuchar) {
      RETURN(unsigned char, i);
    } else
    if (l->rtype == __AVshort) {
      RETURN(short, i);
    } else
    if (l->rtype == __AVushort) {
      RETURN(unsigned short, i);
    } else
    if (l->rtype == __AVint) {
      RETURN(int, i);
    } else
    if (l->rtype == __AVuint) {
      RETURN(unsigned int, i);
    } else
    if (l->rtype == __AVlong) {
      RETURN(long, i);
    } else
    if (l->rtype == __AVulong) {
      RETURN(unsigned long, i);
    } else
    if (l->rtype == __AVlonglong) {
      RETURN(long long, i);
    } else
    if (l->rtype == __AVulonglong) {
      RETURN(unsigned long long, i);
    } else
  /* see above
    if (l->rtype == __AVfloat) {
    } else
    if (l->rtype == __AVdouble) {
    } else
  */
    if (l->rtype == __AVvoidp) {
      RETURN(void*, i);
    } else
    if (l->rtype == __AVstruct) {
      if (l->flags & __AV_PCC_STRUCT_RETURN) {
        /* pcc struct return convention: need a  *(TYPE*)l->raddr = *(TYPE*)i;  */
        if (l->rsize == sizeof(char)) {
          RETURN(char, *(char*)i);
        } else
        if (l->rsize == sizeof(short)) {
          RETURN(short, *(short*)i);
        } else
        if (l->rsize == sizeof(int)) {
          RETURN(int, *(int*)i);
        } else
        if (l->rsize == sizeof(long)) {
          RETURN(long, *(long*)i);
        } else {
          int n = (l->rsize + sizeof(__avword)-1)/sizeof(__avword);
          while (--n >= 0)
            ((__avword*)l->raddr)[n] = ((__avword*)i)[n];
        }
      } else {
        /* normal struct return convention */
        if (l->flags & __AV_REGISTER_STRUCT_RETURN) {
          if (l->rsize == sizeof(char)) {
            RETURN(char, i);
          } else
          if (l->rsize == sizeof(short)) {
            RETURN(short, i);
          } else
          if (l->rsize == sizeof(int)) {
            RETURN(int, i);
          } else
          if (l->rsize == sizeof(long)) {
            RETURN(long, i);
          } else
          if (l->rsize == 2*sizeof(__avword)) {
            ((__avword*)l->raddr)[0] = i;
            ((__avword*)l->raddr)[1] = i2;
          }
        }
      }
    }
  }
  sp += __AV_ALIST_WORDS;
  return 0;
}

#endif /*_avcall_x86_64_c */