#include #include #include #ifdef _MSC_VER #include int mmx_available(void) { return 1; } /* Contrary to MSDN documentation, MMX intrinsics * just plain don't work. */ void increment_mmx(float arr[4]) { arr[0]++; arr[1]++; arr[2]++; arr[3]++; } #elif defined(__MINGW32__) int mmx_available(void) { return 1; } /* MinGW does not seem to ship with MMX or it is broken. */ void increment_mmx(float arr[4]) { arr[0]++; arr[1]++; arr[2]++; arr[3]++; } #else #include #include #if defined(__APPLE__) int mmx_available(void) { return 1; } #else int mmx_available(void) { return __builtin_cpu_supports("mmx"); } #endif void increment_mmx(float arr[4]) { /* Super ugly but we know that values in arr are always small * enough to fit in int16; */ int i; __m64 packed = _mm_set_pi16(arr[3], arr[2], arr[1], arr[0]); __m64 incr = _mm_set1_pi16(1); __m64 result = _mm_add_pi16(packed, incr); /* Should be * int64_t unpacker = _m_to_int64(result); * but it does not exist on 32 bit platforms for some reason. */ int64_t unpacker = (int64_t)(result); _mm_empty(); for(i=0; i<4; i++) { /* This fails on GCC 8 when optimizations are enabled. * Disable it. Patches welcome to fix this. arr[i] = (float)(unpacker & ((1<<16)-1)); unpacker >>= 16; */ arr[i] += 1.0f; } } #endif