OpenBLAS/kernel/simd/intrin_avx.h

#define V_SIMD 256
#define V_SIMD_F64 1
/***************************
 * Data Type
 ***************************/
typedef __m256  v_f32;
#define v_nlanes_f32 8
/***************************
 * Arithmetic
 ***************************/
#define v_add_f32 _mm256_add_ps
#define v_mul_f32 _mm256_mul_ps

#ifdef HAVE_FMA3
    // multiply and add, a*b + c
    #define v_muladd_f32 _mm256_fmadd_ps
#else
    // multiply and add, a*b + c
    BLAS_FINLINE v_f32 v_muladd_f32(v_f32 a, v_f32 b, v_f32 c)
    { return v_add_f32(v_mul_f32(a, b), c); }
#endif // !HAVE_FMA3

// Horizontal add: Calculates the sum of all vector elements.
BLAS_FINLINE float v_sum_f32(__m256 a)
{
    __m256 sum_halves = _mm256_hadd_ps(a, a);
    sum_halves = _mm256_hadd_ps(sum_halves, sum_halves);
    __m128 lo = _mm256_castps256_ps128(sum_halves);
    __m128 hi = _mm256_extractf128_ps(sum_halves, 1);
    __m128 sum = _mm_add_ps(lo, hi);
    return _mm_cvtss_f32(sum);
}

/***************************
 * memory
 ***************************/
// unaligned load
#define v_loadu_f32 _mm256_loadu_ps
#define v_storeu_f32 _mm256_storeu_ps
#define v_setall_f32(VAL) _mm256_set1_ps(VAL)
#define v_zero_f32 _mm256_setzero_ps