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Re: [PATCH, AArch64 10/11] aarch64: Implement TImode compare-and-swap


Hi Richard,

On 26/09/18 06:03, rth7680@gmail.com wrote:
From: Richard Henderson <richard.henderson@linaro.org>

This pattern will only be used with the __sync functions, because
we do not yet have a bare TImode atomic load.

Does this mean that the libatomic `defined(atomic_compare_exchange_n)` checks would return false for 16 bytes sizes?
(the acinclude.m4 file checks for __atomic_compare_exchange_n)

You would know better than I, but if that's the case it seems that the atomic_{load,store}_16 implementations in libatomic would still use the locking ABI, and e.g. atomic_load_16 could be interrupted by using the CASP instruction to produce an incorrect value.


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