OpenBLAS/kernel/x86_64/bf16to.c

/***************************************************************************
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#include <stddef.h>
#include "common.h"

#if defined(DOUBLE)
#define FLOAT_TYPE double
#elif defined(SINGLE)
#define FLOAT_TYPE float
#else
#endif

/* Notes for algorithm:
 * - Input denormal treated as zero
 * - Force to be QNAN
 */
static void bf16to_kernel_1(BLASLONG n, const bfloat16 * in, BLASLONG inc_in, FLOAT_TYPE * out, BLASLONG inc_out)
{
    BLASLONG register index_in  = 0;
    BLASLONG register index_out = 0;
    BLASLONG register index     = 0;
    uint16_t * tmp = NULL;
#if defined(DOUBLE)
    float             float_out = 0.0;
#endif

    while(index<n) {
#if defined(DOUBLE)
        float_out = 0.0;
        tmp = (uint16_t*)(&float_out);
#else
        *(out+index_out) = 0;
        tmp = (uint16_t*)(out+index_out);
#endif

        switch((*(in+index_in)) & 0xff80u) {
            case (0x0000u):   /* Type 1: Positive denormal */
                tmp[1] = 0x0000u;
                tmp[0] = 0x0000u;
                break;
            case (0x8000u):   /* Type 2: Negative denormal */
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
                tmp[1] = 0x8000u;
                tmp[0] = 0x0000u;
#else
                tmp[1] = 0x0000u;
                tmp[0] = 0x8000u;
#endif
                break;
            case (0x7f80u):   /* Type 3: Positive infinity or NAN */
            case (0xff80u):   /* Type 4: Negative infinity or NAN */
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
                tmp[1] = *(in+index_in);
#else
                tmp[0] = *(in+index_in);
#endif
                /* Specific for NAN */
                if (((*(in+index_in)) & 0x007fu) != 0) {
                    /* Force to be QNAN */
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
                    tmp[1] |= 0x0040u;
#else
                    tmp[0] |= 0x0040u;
#endif
                }
                break;
            default:              /* Type 5: Normal case */
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
                tmp[1] = *(in+index_in);
#else
                tmp[0] = *(in+index_in);
#endif
                break;
        }
#if defined(DOUBLE)
	*(out+index_out) = (double)float_out;
#endif
        index_in  += inc_in;
        index_out += inc_out;
        index++;
    }
}

void CNAME(BLASLONG n, bfloat16 * in, BLASLONG inc_in, FLOAT_TYPE * out, BLASLONG inc_out)
{
    if (n <= 0)  return;

    bf16to_kernel_1(n, in, inc_in, out, inc_out);
}