/* 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