diff options
| -rw-r--r-- | c/blake3_dispatch.c | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/c/blake3_dispatch.c b/c/blake3_dispatch.c index 8e0c531..568d28f 100644 --- a/c/blake3_dispatch.c +++ b/c/blake3_dispatch.c @@ -62,7 +62,12 @@ static void cpuidex(uint32_t out[4], uint32_t id, uint32_t sid) { #endif #if defined(IS_X86) // only define cpu_feature on x86 + +// stdatomic.h is not yet available under MSVC +#if !defined(_MSC_VER) #include <stdatomic.h> +#endif + enum cpu_feature { SSE2 = 1 << 0, SSSE3 = 1 << 1, @@ -78,7 +83,11 @@ enum cpu_feature { #if !defined(BLAKE3_TESTING) static /* Allow the variable to be controlled manually for testing */ #endif - atomic_int g_cpu_features = UNDEFINED; +#if defined(_MSC_VER) + long g_cpu_features = UNDEFINED; +#else +atomic_int g_cpu_features = UNDEFINED; +#endif #if !defined(BLAKE3_TESTING) static @@ -86,7 +95,13 @@ static enum cpu_feature get_cpu_features() { +#if defined(_MSC_VER) + // This ordinary load is effectively a relaxed atomic under MSVC. + // https://docs.microsoft.com/en-us/windows/win32/sync/interlocked-variable-access + long load = g_cpu_features; +#else int load = atomic_load_explicit(&g_cpu_features, memory_order_relaxed); +#endif if (load != UNDEFINED) { return (enum cpu_feature)load; } else { @@ -127,7 +142,13 @@ static } } } +#if defined(_MSC_VER) + // This ordinary store is effectively a relaxed atomic under MSVC. + // https://docs.microsoft.com/en-us/windows/win32/sync/interlocked-variable-access + g_cpu_features = (long)features; +#else atomic_store_explicit(&g_cpu_features, (int)features, memory_order_relaxed); +#endif return features; #else /* How to detect NEON? */ |