// Low-level functions for atomic operations: Sparc32 version  -*- C++ -*-

// Copyright (C) 1999, 2000, 2001 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.

#ifndef _BITS_ATOMICITY_H
#define _BITS_ATOMICITY_H	1

typedef int _Atomic_word;

static int
__attribute__ ((__unused__))
__exchange_and_add (volatile _Atomic_word* __mem, int __val)
{
  static unsigned char __lock;
  _Atomic_word __result, __tmp;

  __asm__ __volatile__("1:	ldstub	[%1], %0\n\t"
		       "	cmp	%0, 0\n\t"
		       "	bne	1b\n\t"
		       "	 nop"
		       : "=&r" (__tmp)
		       : "r" (&__lock)
		       : "memory");
  __result = *__mem;
  *__mem += __val;
  __asm__ __volatile__("stb	%%g0, [%0]"
		       : /* no outputs */
		       : "r" (&__lock)
		       : "memory");
  return __result;
}

static void
__attribute__ ((__unused__))
__atomic_add (volatile _Atomic_word* __mem, int __val)
{
  static unsigned char __lock;
  _Atomic_word __tmp;

  __asm__ __volatile__("1:	ldstub	[%1], %0\n\t"
		       "	cmp	%0, 0\n\t"
		       "	bne	1b\n\t"
		       "	 nop"
		       : "=&r" (__tmp)
		       : "r" (&__lock)
		       : "memory");
  *__mem += __val;
  __asm__ __volatile__("stb	%%g0, [%0]"
		       : /* no outputs */
		       : "r" (&__lock)
		       : "memory");
}

static int
__attribute__ ((__unused__))
__compare_and_swap (volatile long *__p, long __oldval, long __newval)
{
  static unsigned char __lock;
  long __ret, __tmp;

  __asm__ __volatile__("1:	ldstub	[%1], %0\n\t"
		       "	cmp	%0, 0\n\t"
		       "	bne	1b\n\t"
		       "	 nop"
		       : "=&r" (__tmp)
		       : "r" (&__lock)
		       : "memory");
  if (*__p != __oldval)
    __ret = 0;
  else
    {
      *__p = __newval;
      __ret = 1;
    }
  __asm__ __volatile__("stb	%%g0, [%0]"
		       : /* no outputs */
		       : "r" (&__lock)
		       : "memory");

  return __ret;
}

#endif /* atomicity.h */
