rs6000-c.c

gcc-you can use this code to learn something about gcc, and inquire further into linux,

/* Subroutines for the C front end on the POWER and PowerPC architectures.
   Copyright (C) 2002
   Free Software Foundation, Inc.

   Contributed by Zack Weinberg <[e-mail]>

This file is part of GNU CC.

GNU CC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU CC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

#include "config.h"
#include "system.h"
#include "cpplib.h"
#include "tree.h"
#include "c-pragma.h"
#include "errors.h"
#include "tm_p.h"

/* Handle the machine specific pragma longcall.  Its syntax is

   # pragma longcall ( TOGGLE )

   where TOGGLE is either 0 or 1.

   rs6000_default_long_calls is set to the value of TOGGLE, changing
   whether or not new function declarations receive a longcall
   attribute by default.  */

#define SYNTAX_ERROR(msgid) do {					\
  warning (msgid);					\
  warning ("ignoring malformed #pragma longcall");	\
  return;						\
} while (0)

void
rs6000_pragma_longcall (pfile)
     cpp_reader *pfile ATTRIBUTE_UNUSED;
{
  tree x, n;

  /* If we get here, generic code has already scanned the directive
     leader and the word "longcall".  */

  if (c_lex (&x) != CPP_OPEN_PAREN)
    SYNTAX_ERROR ("missing open paren");
  if (c_lex (&n) != CPP_NUMBER)
    SYNTAX_ERROR ("missing number");
  if (c_lex (&x) != CPP_CLOSE_PAREN)
    SYNTAX_ERROR ("missing close paren");

  if (n != integer_zero_node && n != integer_one_node)
    SYNTAX_ERROR ("number must be 0 or 1");

  if (c_lex (&x) != CPP_EOF)
    warning ("junk at end of #pragma longcall");

  rs6000_default_long_calls = (n == integer_one_node);
}

/* Handle defining many CPP flags based on TARGET_xxx.  As a general
   policy, rather than trying to guess what flags a user might want a
   #define for, it's better to define a flag for everything.  */

#define builtin_define(TXT) cpp_define (pfile, TXT)
#define builtin_assert(TXT) cpp_assert (pfile, TXT)

void
rs6000_cpu_cpp_builtins (pfile)
     cpp_reader *pfile;
{
  if (TARGET_POWER2)
    builtin_define ("_ARCH_PWR2");
  else if (TARGET_POWER)
    builtin_define ("_ARCH_PWR");
  if (TARGET_POWERPC)
    builtin_define ("_ARCH_PPC");
  if (TARGET_POWERPC64)
    builtin_define ("_ARCH_PPC64");
  if (! TARGET_POWER && ! TARGET_POWER2 && ! TARGET_POWERPC)
    builtin_define ("_ARCH_COM");
  if (TARGET_ALTIVEC)
    builtin_define ("__ALTIVEC__");
  if (TARGET_SPE)
    builtin_define ("__SPE__");
  if (TARGET_SOFT_FLOAT)
    builtin_define ("_SOFT_FLOAT");
  /* Used by lwarx/stwcx. errata work-around.  */
  if (rs6000_cpu == PROCESSOR_PPC405)
    builtin_define ("__PPC405__");

  /* May be overridden by target configuration.  */
  RS6000_CPU_CPP_ENDIAN_BUILTINS();

  if (TARGET_LONG_DOUBLE_128)
    builtin_define ("__LONG_DOUBLE_128__");

  switch (rs6000_current_abi)
    {
    case ABI_V4:
      builtin_define ("_CALL_SYSV");
      break;
    case ABI_AIX_NODESC:
      builtin_define ("_CALL_AIX");
      break;
    case ABI_AIX:
      builtin_define ("_CALL_AIXDESC");
      builtin_define ("_CALL_AIX");
      break;
    case ABI_DARWIN:
      builtin_define ("_CALL_DARWIN");
      break;
    default:
      break;
    }
}