74 строки
1.7 KiB
C
74 строки
1.7 KiB
C
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/*
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* $HEADER$
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*/
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#ifndef LAM_SYS_ATOMIC_H_INCLUDED
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#define LAM_SYS_ATOMIC_H_INCLUDED
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#ifdef SMP
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#define LOCK "lock; "
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#else
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#define LOCK
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#endif
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/*
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* On ia32, we use cmpxchg.
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*/
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static inline int lam_atomic_cmpset_acq_32(volatile uint32_t *addr,
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uint32_t cmp,
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uint32_t new)
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{
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uint32_t ret = cmp;
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__asm __volatile (
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LOCK "cmpxchgl %1,%2; "
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"setz %%al; "
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"movzbl %%al,%0; "
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: "+a" (ret)
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: "r" (new), "m" (*addr)
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: "memory");
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return (ret == cmp);
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}
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static inline int lam_atomic_cmpset_rel_32(volatile uint32_t *addr,
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uint32_t cmp,
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uint32_t new)
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{
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return lam_atomic_cmpset_acq_32(addr, cmp, new);
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}
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static inline int lam_atomic_cmpset_acq_64(volatile uint64_t *addr,
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uint64_t cmp,
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uint64_t new)
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{
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/*
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* Compare EDX:EAX with m64. If equal, set ZF and load ECX:EBX into
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* m64. Else, clear ZF and load m64 into EDX:EAX.
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*/
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uint64_t ret = cmp;
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struct { uint32_t lo; uint32_t hi; } *p = (struct lwords *) &new;
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__asm __volatile(
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LOCK "cmpxchg8b %1"
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: "+A" (ret)
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: "m" (*addr), "b" (p->lo), "c" (p->hi)
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: "memory");
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return (ret == cmp);
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}
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static inline int lam_atomic_cmpset_rel_64(volatile uint64_t *addr,
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uint64_t cmp,
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uint64_t new)
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{
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return lam_atomic_cpmset_acq_64(addr, cmp, new);
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}
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#endif /* ! LAM_SYS_ATOMIC_H_INCLUDED */
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