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| | /*
* Atomic compare and exchange: Compare OLD with MEM, if identical,
* store NEW in MEM. Return the initial value in MEM. Success is
* indicated by comparing RETURN with OLD.
*/
#define __cmpxchg(ptr, old, new, op_suffix) \
({ \
__typeof((ptr)) __cxc__ptr = (ptr); \
register unsigned long __cxc__rn __asm__("$r62") = (unsigned long) (new); \
register unsigned long __cxc__ro __asm__("$r63") = (unsigned long) (old); \
do { \
__asm__ __volatile__ ( \
"acswap" #op_suffix " 0[%[rPtr]], $r62r63\n" \
: "+r" (__cxc__rn), "+r" (__cxc__ro) \
: [rPtr] "r" (__cxc__ptr) \
: "memory"); \
/* Success */ \
if (__cxc__rn) { \
__cxc__ro = (unsigned long) (old); \
break; \
} \
/* We failed, read value */ \
__cxc__ro = (unsigned long) *(__cxc__ptr); \
if (__cxc__ro != (unsigned long) (old)) \
break; \
/* __cxc__rn has been cloberred by cmpxch result */ \
__cxc__rn = (unsigned long) (new); \
} while (1); \
(__cxc__ro); \
})
#define cmpxchg(ptr, o, n) \
({ \
unsigned long __cmpxchg__ret; \
switch (sizeof(*(ptr))) { \
case 4: \
__cmpxchg__ret = __cmpxchg((ptr), (o), (n), w); \
break; \
case 8: \
__cmpxchg__ret = __cmpxchg((ptr), (o), (n), d); \
break; \
} \
(__typeof(*(ptr))) (__cmpxchg__ret); \
})
#define a_cas a_cas
static inline int a_cas(volatile int *p, int t, int s)
{
return cmpxchg(p, t, s);
}
#define a_cas_p a_cas_p
static inline void *a_cas_p(volatile void *p, void *t, void *s)
{
return (void *)a_cas(p, (uintptr_t)t, (uintptr_t)s);
}
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