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Diffstat (limited to 'cas.h')
| -rw-r--r-- | cas.h | 40 |
1 files changed, 40 insertions, 0 deletions
@@ -0,0 +1,40 @@ +/* + * File : cas.c + * Author : Jérémy Zurcher <jeremy@asynk.ch> + * Date : 01/11/09 + * License : + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE + * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION + * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION + * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + * + */ + +/* CMPXCHG8B m64 Compare EDX:EAX with m64. If equal, set ZF and load ECX:EBX into m64. Else, clear ZF and load m64 into EDX:EAX. */ +static inline unsigned int compare_and_swap(volatile unsigned long long *mem, + volatile unsigned long long old, + volatile unsigned long long new) { + char result; + __asm__ __volatile__("lock; cmpxchg8b %0; setz %1;" + : "=m"(*mem), "=q"(result) + : "m"(*mem), "d" ((unsigned long)(old>>32)), "a" ((unsigned long)old), + "c" ((unsigned long)(new>>32)), "b" ((unsigned long)new) + : "memory"); + return (int)result; +} + |