avcall-rs6000.c

c++写的一个脚本解释器

#ifndef _avcall_rs6000_c				/*-*- C -*-*/
#define _avcall_rs6000_c
/**
  Copyright 1993 Bill Triggs, <[e-mail]>
  Copyright 1995-1999 Bruno Haible, <[e-mail]>
  Copyright 2000 Adam Fedor, <[e-mail]>
  Copyright 2004 Paul Guyot, <[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 !!!

  Foreign function interface for an IBM RS/6000 with gcc

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

  RS6000 Argument Passing Conventions:

  All arguments, except the first 8 words, are passed on the stack with
  word alignment. Doubles take two words. The first 13 doubles and floats
  are also passed in floating-point-registers.
  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.

  Differences between AIX and SysV.4 argument passing conventions:
  - AIX: the first 13 doubles and floats are passed in FP registers,
         and when they do, there is still room allocated for them in the
         argument sequence (integer regs or stack).
    SysV.4: the first 8 doubles and floats are passed in FP registers,
         and no room is allocated for them in the argument sequence.
  - AIX: Structures are passed in the argument sequence.
    SysV.4: Structures are passed by reference: only a pointer appears in
         the argument sequence.
  - AIX: Long longs are only word aligned.
    SysV.4: Long longs are two-word aligned, both when passed in registers
         (pairs: 3/4, 5/6, 7/8, 9/10) and when passed on the stack. (Recall
         that the stack is always 8-byte aligned).

  Compile this routine with gcc -O (or -O2 -fno-omit-frame-pointer or -g -O)
  to get the right register variables. For other compilers use the
  pre-compiled assembler version.
  ----------------------------------------------------------------------*/
#include "avcall.h.in"

#ifdef __linux__
#define STACK_OFFSET 2
#else
#define STACK_OFFSET 14
#endif

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

register double farg1	__asm__("fr1");
register double farg2	__asm__("fr2");
register double farg3	__asm__("fr3");
register double farg4	__asm__("fr4");
register double farg5	__asm__("fr5");
register double farg6	__asm__("fr6");
register double farg7	__asm__("fr7");
register double farg8	__asm__("fr8");
register double farg9	__asm__("fr9");
register double farg10	__asm__("fr10");
register double farg11	__asm__("fr11");
register double farg12	__asm__("fr12");
register double farg13	__asm__("fr13");

int
__builtin_avcall(av_alist* l)
{
  register __avword*	sp	__asm__("r1");  /* C names for registers */
/*register __avword	iret	__asm__("r3"); */
  register __avword	iret2	__asm__("r4");
  register float	fret	__asm__("fr1");
  register double	dret	__asm__("fr1");

  __avword space[__AV_ALIST_WORDS];	/* space for callee's stack frame */
  __avword* argframe = sp + STACK_OFFSET;/* stack offset for argument list */
  int arglen = l->aptr - l->args;
#if defined(_AIX) || (defined(__MACH__) && defined(__APPLE__))
  int farglen = 0;
#else
  int farglen = l->faptr - l->fargs;
#endif
  __avword i;

  for (i = (8-farglen); i < arglen; i++) /* push function args onto stack */
    argframe[i-8+farglen] = l->args[i];

  /* pass first 13 floating-point args in registers */
  arglen = l->faptr - l->fargs;
  if (arglen == 0) goto fargs0;
  else if (arglen == 1) goto fargs1;
  else if (arglen == 2) goto fargs2;
  else if (arglen == 3) goto fargs3;
  else if (arglen == 4) goto fargs4;
  else if (arglen == 5) goto fargs5;
  else if (arglen == 6) goto fargs6;
  else if (arglen == 7) goto fargs7;
  else if (arglen == 8) goto fargs8;
  else if (arglen == 9) goto fargs9;
  else if (arglen == 10) goto fargs10;
  else if (arglen == 11) goto fargs11;
  else if (arglen == 12) goto fargs12;
  else if (arglen == 13) goto fargs13;
  fargs13: farg13 = l->fargs[12];
  fargs12: farg12 = l->fargs[11];
  fargs11: farg11 = l->fargs[10];
  fargs10: farg10 = l->fargs[9];
  fargs9: farg9 = l->fargs[8];
  fargs8: farg8 = l->fargs[7];
  fargs7: farg7 = l->fargs[6];
  fargs6: farg6 = l->fargs[5];
  fargs5: farg5 = l->fargs[4];
  fargs4: farg4 = l->fargs[3];
  fargs3: farg3 = l->fargs[2];
  fargs2: farg2 = l->fargs[1];
  fargs1: farg1 = l->fargs[0];
  fargs0: ;
				/* call function, pass 8 args in registers */
  i = (*l->func)(l->args[0], l->args[1], l->args[2], l->args[3],
		 l->args[4], l->args[5], l->args[6], l->args[7]);

  /* 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 || l->rtype == __AVulonglong) {
    ((__avword*)l->raddr)[0] = i;
    ((__avword*)l->raddr)[1] = iret2;
  } else
  if (l->rtype == __AVfloat) {
    RETURN(float, fret);
  } else
  if (l->rtype == __AVdouble) {
    RETURN(double, dret);
  } 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(double)) {
        ((int*)l->raddr)[0] = ((int*)i)[0];
        ((int*)l->raddr)[1] = ((int*)i)[1];
      } 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 == 2*sizeof(__avword)) {
          ((__avword*)l->raddr)[0] = i;
          ((__avword*)l->raddr)[1] = iret2;
        }
      }
    }
  }
  return 0;
}

#endif /*_avcall_rs6000_c */