OpenBLAS/kernel/x86_64/stobf16_microk_cooperlake.c

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/* need a new enough GCC for avx512 support */
#if (( defined(__GNUC__)  && __GNUC__   >= 10 && defined(__AVX512BF16__)) || (defined(__clang__) && __clang_major__ >= 9))

#define HAVE_TOBF16_ACCL_KERNEL 1
#include "common.h"
#include <immintrin.h>

static void tobf16_accl_kernel(BLASLONG n, const float * in, bfloat16 * out)
{
    /* Get the 64-bytes unaligned header number targeting for avx512
     * processing (Assume input float array is natural aligned) */
    int align_header = ((64 - ((uintptr_t)in & (uintptr_t)0x3f)) >> 2) & 0xf;

    if (n < align_header) {align_header = n;}

    if (align_header != 0) {
        uint16_t align_mask16 = (((uint16_t)0xffff) >> (16-align_header));
        __m512 a = _mm512_maskz_loadu_ps(*((__mmask16*) &align_mask16), &in[0]);
        _mm256_mask_storeu_epi16(&out[0], *((__mmask16*) &align_mask16), (__m256i) _mm512_cvtneps_pbh(a));
    }

    if (n == align_header) {
        return;
    } else {
        n -= align_header;
        in += align_header;
        out += align_header;
    }

    int tail_index_32  = n&(~31);
    int tail_index_128 = n&(~127);
    uint32_t tail_mask32 = (((uint32_t) 0xffffffff) >> (32-(n&31)));
    uint16_t tail_mask16 = (((uint16_t) 0xffff)     >> (16-(n&15)));

    /* Processing the main chunk with 128-elements per round */
    for (int i = 0; i < tail_index_128; i += 128) {
        _mm512_storeu_si512(&out[i+ 0], (__m512i) _mm512_cvtne2ps_pbh(_mm512_load_ps(&in[i+ 16]), _mm512_load_ps(&in[i+ 0])));
        _mm512_storeu_si512(&out[i+32], (__m512i) _mm512_cvtne2ps_pbh(_mm512_load_ps(&in[i+ 48]), _mm512_load_ps(&in[i+32])));
        _mm512_storeu_si512(&out[i+64], (__m512i) _mm512_cvtne2ps_pbh(_mm512_load_ps(&in[i+ 80]), _mm512_load_ps(&in[i+64])));
        _mm512_storeu_si512(&out[i+96], (__m512i) _mm512_cvtne2ps_pbh(_mm512_load_ps(&in[i+112]), _mm512_load_ps(&in[i+96])));
    }

    /* Processing the remaining <128 chunk with 32-elements per round */
    for (int j = tail_index_128; j < tail_index_32; j += 32) {
        _mm512_storeu_si512(&out[j], (__m512i) _mm512_cvtne2ps_pbh(_mm512_load_ps(&in[j+ 16]), _mm512_load_ps(&in[j])));
    }

    /* Processing the remaining <32 chunk with masked processing */
    if ((n&31) > 15) {
        __m512 b = _mm512_load_ps(&in[tail_index_32]);
        __m512 a = _mm512_maskz_load_ps(*((__mmask16*) &tail_mask16), &in[tail_index_32+16]);
        _mm512_mask_storeu_epi16(&out[tail_index_32], *((__mmask32*) &tail_mask32), (__m512i) _mm512_cvtne2ps_pbh(a, b));
    } else if ((n&31) > 0) {
        __m512 a = _mm512_maskz_load_ps(*((__mmask16*) &tail_mask16), &in[tail_index_32]);
        _mm256_mask_storeu_epi16(&out[tail_index_32], *((__mmask16*) &tail_mask16), (__m256i) _mm512_cvtneps_pbh(a));
    }
}

#endif