/* $OpenBSD: _atomic_lock.c,v 1.1 2017/08/15 06:13:24 guenther Exp $ */ /* * Copyright (c) 2005 Marco Peereboom * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include #ifdef DIAGNOSTIC #include #include #endif int _atomic_lock(volatile _atomic_lock_t *lock) { volatile _atomic_lock_t old; #ifdef DIAGNOSTIC if ((unsigned long)lock & 0xf) { printf("lock not 16 byte aligned\n"); abort(); } #endif asm volatile ("ldcws 0(%2),%0" : "=&r" (old), "+m" (lock) : "r" (lock)); return (old == _ATOMIC_LOCK_LOCKED); }