OpenBLAS/kernel/x86_64/sasum.c

#include "common.h"

#if defined(DOUBLE)
#error supports float only
#else
#ifndef ABS_K
#define ABS_K(a) ((a) > 0 ? (a) : (-(a)))
#endif

#endif

#if defined(SKYLAKEX)
#include "sasum_microk_skylakex-2.c"
#elif defined(HASWELL)
#include "sasum_microk_haswell-2.c"
#endif

#ifndef HAVE_SASUM_KERNEL

static FLOAT sasum_kernel(BLASLONG n, FLOAT *x1)
{

    BLASLONG i=0;
    BLASLONG n_8 = n & -8;
    FLOAT *x = x1;
    FLOAT temp0, temp1, temp2, temp3;
    FLOAT temp4, temp5, temp6, temp7;
    FLOAT sum0 = 0.0;
    FLOAT sum1 = 0.0;
    FLOAT sum2 = 0.0;
    FLOAT sum3 = 0.0;
    FLOAT sum4 = 0.0;

    while (i < n_8) {

        temp0 = ABS_K(x[0]);
        temp1 = ABS_K(x[1]);
        temp2 = ABS_K(x[2]);
        temp3 = ABS_K(x[3]);
        temp4 = ABS_K(x[4]);
        temp5 = ABS_K(x[5]);
        temp6 = ABS_K(x[6]);
        temp7 = ABS_K(x[7]);

        sum0 += temp0;
        sum1 += temp1;
        sum2 += temp2;
        sum3 += temp3;

        sum0 += temp4;
        sum1 += temp5;
        sum2 += temp6;
        sum3 += temp7;

        x+=8;
        i+=8;

    }

    while (i < n) {
        sum4 += ABS_K(x1[i]);
        i++;
    }

    return sum0+sum1+sum2+sum3+sum4;
}

#endif

static FLOAT asum_compute(BLASLONG n, FLOAT * x, BLASLONG inc_x)
{
    BLASLONG i = 0;
    FLOAT sumf = 0.0;
    
    if (n <= 0 || inc_x <= 0) return (sumf);

    if (inc_x == 1) {
        sumf = sasum_kernel(n, x);
    }
    else {
        n *= inc_x;
        while(i < n) {
            sumf += ABS_K(x[i]);
            i += inc_x;
        }
    }
    return (sumf);
}

#if defined(SMP)
static int asum_thread_function(BLASLONG n, BLASLONG dummy0, BLASLONG dummy1, FLOAT dummy2, FLOAT *x, BLASLONG inc_x, FLOAT *dummy3, BLASLONG dummy4, FLOAT *result, BLASLONG dummy5)
{
    *(FLOAT *)result = asum_compute(n, x, inc_x);
    return 0;
}

extern int blas_level1_thread_with_return_value(int mode, BLASLONG m, BLASLONG n, BLASLONG k, void * alpha, void *a, BLASLONG lda, void *b, BLASLONG ldb, void *c, BLASLONG ldc, int(*function)(), int nthreads);
#endif

FLOAT CNAME(BLASLONG n, FLOAT *x, BLASLONG inc_x)
{
#if defined(SMP)
    int nthreads;
    FLOAT dummy_alpha;
#endif
    FLOAT sumf = 0.0;

#if defined(SMP)
    int num_cpu = num_cpu_avail(1);
    if (n <= 100000 || inc_x <= 0)
        nthreads = 1;
    else
        nthreads = num_cpu < n/100000 ? num_cpu : n/100000;
    if (nthreads == 1) {
        sumf = asum_compute(n, x, inc_x);
    }
    else {
        int mode, i;
        char result[MAX_CPU_NUMBER * sizeof(double) *2];
        FLOAT * ptr;
#if !defined(DOUBLE)
        mode = BLAS_SINGLE | BLAS_REAL;
#else
        mode = BLAS_DOUBLE | BLAS_REAL;
#endif
        blas_level1_thread_with_return_value(mode, n, 0, 0, &dummy_alpha, x, inc_x, NULL, 0, result, 0, (void *)asum_thread_function, nthreads);
        ptr = (FLOAT *)result;
        for (i = 0; i < nthreads; i++) {
            sumf += (*ptr);
            ptr = (FLOAT *)(((char *)ptr) + sizeof(double) * 2);
        }
    }
#else
    sumf = asum_compute(n, x, inc_x);
#endif
    return(sumf);
}