atomicity.h   [plain text]

// Low-level functions for atomic operations: PowerPC version  -*- C++ -*-

// Copyright (C) 1999, 2000, 2001, 2003, 2004 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library 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.

// This library 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 this library; see the file COPYING.  If not, write to the Free
// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// USA.

// As a special exception, you may use this file as part of a free software
// library without restriction.  Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License.  This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.

#include <bits/atomicity.h>

#ifdef __PPC405__
#define _STWCX "sync \n\tstwcx. "
#else
#define _STWCX "stwcx. "
#endif

namespace __gnu_cxx
{
  _Atomic_word
  __attribute__ ((__unused__))
  __exchange_and_add(volatile _Atomic_word* __mem, int __val)
  {
    _Atomic_word __tmp, __res;
    __asm__ __volatile__ (
			  "/* Inline exchange & add */\n"
			  "0:\t"
			  "lwarx    %0,0,%3 \n\t"
			  "add%I4   %1,%0,%4 \n\t"
			  _STWCX "  %1,0,%3 \n\t"
			  "bne-     0b \n\t"
			  "/* End exchange & add */"
			  : "=&b"(__res), "=&r"(__tmp), "=m" (*__mem)
			  : "r" (__mem), "Ir"(__val), "m" (*__mem)
			  : "cr0");
    return __res;
  }
  
  void
  __attribute__ ((__unused__))
  __atomic_add(volatile _Atomic_word* __mem, int __val)
  {
    _Atomic_word __tmp;
    __asm__ __volatile__ (
			  "/* Inline atomic add */\n"
			  "0:\t"
			  "lwarx    %0,0,%2 \n\t"
			  "add%I3   %0,%0,%3 \n\t"
			  _STWCX "  %0,0,%2 \n\t"
			  "bne-     0b \n\t"
			  "/* End atomic add */"
			  : "=&b"(__tmp), "=m" (*__mem)
			  : "r" (__mem), "Ir"(__val), "m" (*__mem)
			  : "cr0");
  }
} // namespace __gnu_cxx