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atomic_is_lock_free.c revision 1.3.2.3 
      1  1.3.2.3  martin /*	$NetBSD: atomic_is_lock_free.c,v 1.3.2.3 2023/12/14 17:49:40 martin Exp $	*/
      2  1.3.2.2  martin 
      3  1.3.2.2  martin /*-
      4  1.3.2.2  martin  * Copyright (c) 2023 The NetBSD Foundation, Inc.
      5  1.3.2.2  martin  * All rights reserved.
      6  1.3.2.2  martin  *
      7  1.3.2.2  martin  * Redistribution and use in source and binary forms, with or without
      8  1.3.2.2  martin  * modification, are permitted provided that the following conditions
      9  1.3.2.2  martin  * are met:
     10  1.3.2.2  martin  * 1. Redistributions of source code must retain the above copyright
     11  1.3.2.2  martin  *    notice, this list of conditions and the following disclaimer.
     12  1.3.2.2  martin  * 2. Redistributions in binary form must reproduce the above copyright
     13  1.3.2.2  martin  *    notice, this list of conditions and the following disclaimer in the
     14  1.3.2.2  martin  *    documentation and/or other materials provided with the distribution.
     15  1.3.2.2  martin  *
     16  1.3.2.2  martin  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     17  1.3.2.2  martin  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     18  1.3.2.2  martin  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     19  1.3.2.2  martin  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     20  1.3.2.2  martin  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     21  1.3.2.2  martin  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     22  1.3.2.2  martin  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     23  1.3.2.2  martin  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     24  1.3.2.2  martin  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     25  1.3.2.2  martin  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     26  1.3.2.2  martin  * POSSIBILITY OF SUCH DAMAGE.
     27  1.3.2.2  martin  */
     28  1.3.2.2  martin 
     29  1.3.2.2  martin #include <sys/cdefs.h>
     30  1.3.2.3  martin __RCSID("$NetBSD: atomic_is_lock_free.c,v 1.3.2.3 2023/12/14 17:49:40 martin Exp $");
     31  1.3.2.2  martin 
     32  1.3.2.2  martin #include <sys/types.h>
     33  1.3.2.2  martin 
     34  1.3.2.2  martin #include <sys/stdbool.h>
     35  1.3.2.2  martin 
     36  1.3.2.3  martin /*
     37  1.3.2.3  martin  * XXX Work around clang's built-in __atomic_is_lock_free by having the
     38  1.3.2.3  martin  * C name be different but using an asm rename to define the right
     39  1.3.2.3  martin  * symbol.
     40  1.3.2.3  martin  */
     41  1.3.2.3  martin bool __atomic_is_lock_free_hack(size_t, const volatile void *)
     42  1.3.2.3  martin     __RENAME(__atomic_is_lock_free);
     43  1.3.2.3  martin #define	__atomic_is_lock_free	__atomic_is_lock_free_hack
     44  1.3.2.3  martin 
     45  1.3.2.2  martin bool
     46  1.3.2.2  martin __atomic_is_lock_free(size_t n, const volatile void *p __unused)
     47  1.3.2.2  martin {
     48  1.3.2.2  martin 
     49  1.3.2.2  martin 	switch (n) {
     50  1.3.2.2  martin 	case 1:
     51  1.3.2.2  martin 		return __atomic_always_lock_free(1, 0);
     52  1.3.2.2  martin 	case 2:
     53  1.3.2.2  martin 		return __atomic_always_lock_free(2, 0);
     54  1.3.2.2  martin 	case 4:
     55  1.3.2.2  martin 		return __atomic_always_lock_free(4, 0);
     56  1.3.2.2  martin 	case 8:
     57  1.3.2.2  martin 		return __atomic_always_lock_free(8, 0);
     58  1.3.2.2  martin 	case 16:
     59  1.3.2.2  martin 		return __atomic_always_lock_free(16, 0);
     60  1.3.2.2  martin 	default:
     61  1.3.2.2  martin 		return false;
     62  1.3.2.2  martin 	}
     63  1.3.2.2  martin }
     64