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/* Atomic operations. i386 version.
Copyright (C) 2000 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#ifndef _BITS_ATOMIC_H
#define _BITS_ATOMIC_H 1
typedef __volatile int __atomic_t;
static inline void
__atomic_inc (__atomic_t *__var)
{
__asm__ __volatile ("lock; incl %0" : "=m" (*__var) : "m" (*__var));
}
static inline void
__atomic_dec (__atomic_t *__var)
{
__asm__ __volatile ("lock; decl %0" : "=m" (*__var) : "m" (*__var));
}
static inline int
__atomic_dec_and_test (__atomic_t *__var)
{
unsigned char __ret;
__asm__ __volatile ("lock; decl %0; sete %1"
: "=m" (*__var), "=qm" (__ret) : "m" (*__var));
return __ret != 0;
}
/* We assume that an __atomicptr_t is only used for pointers to
word-aligned objects, and use the lowest bit for a simple lock. */
typedef __volatile int * __atomicptr_t;
/* Actually we don't implement that yet, and assume that we run on
something that has the i486 instruction set. */
static inline int
__atomicptr_compare_and_swap (__atomicptr_t *__ptr, void *__oldval,
void * __newval)
{
char __ret;
int __dummy;
__asm__ __volatile ("lock; cmpxchgl %3, %1; sete %0"
: "=q" (__ret), "=m" (*__ptr), "=a" (__dummy)
: "r" (__newval), "m" (*__ptr), "a" (__oldval));
return __ret;
}
#endif
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