OSCompareAndSwap(Mac OS X)是否等于CMPXCHG8B?
最佳答案
您可以在XNU源代码的OSAtomic.s文件中找到原子函数的定义。例如,以下是1486.2.11中的OSAtomicCompareAndSwapPtr for x86_64:
_OSCompareAndSwap64:
_OSCompareAndSwapPtr: #;oldValue, newValue, ptr
movq %rdi, %rax
lock
cmpxchgq %rsi, 0(%rdx) #; CAS (eax is an implicit operand)
sete %al #; did CAS succeed? (TZ=1)
movzbq %al, %rax #; clear out the high bytes
ret