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/*
* File : lf_cas.h
* 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.
*
*/
#ifndef _LF_CAS_H_
#define _LF_CAS_H_
# ifdef __cplusplus
extern "C" {
# endif /* __cplusplus */
struct lf_pointer;
typedef struct lf_pointer {
volatile struct lf_pointer *ptr;
volatile unsigned int count;
} lf_pointer_t;
union ptr_u {
lf_pointer_t ptr;
volatile long long concat;
};
#define lf_eql(ptra,ptrb) (((union ptr_u)(ptra)).concat == ((union ptr_u)(ptrb)).concat)
/* 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 cas( volatile lf_pointer_t *mem,
volatile lf_pointer_t old,
volatile lf_pointer_t new ) {
char result;
__asm__ __volatile__("lock; cmpxchg8b %0; setz %1;"
: "=m"(*mem), "=q"(result)
: "m"(*mem), "d" (old.count), "a" (old.ptr),
"c" (new.count), "b" (new.ptr)
: "memory");
return (int)result;
}
# ifdef __cplusplus
}
# endif /* __cplusplus */
# endif /* _LF_CAS_H_ */
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