OpenBLAS/kernel/zarch/idamax.c

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#include "common.h"
#include <math.h>

#if defined(DOUBLE)

#define ABS fabs

#else

#define ABS fabsf

#endif

 
/**
 * Find  maximum index 
 * Warning: requirements n>0  and n % 32 == 0
 * @param n     
 * @param x     pointer to the vector
 * @param maxf  (out) maximum absolute value .( only for output )
 * @return  index 
 */
static BLASLONG diamax_kernel_32_TUNED(BLASLONG n, FLOAT *x, FLOAT *maxf) {
    BLASLONG index;
   __asm__(
            "pfd 1, 0(%[ptr_x])      \n\t"
            "sllg   %%r0,%[n],3      \n\t"
            "agr    %%r0,%[ptr_x]    \n\t"
            "vleig  %%v20,0,0  \n\t"
            "vleig  %%v20,1,1  \n\t"
            "vleig  %%v21,2,0  \n\t"
            "vleig  %%v21,3,1  \n\t"
            "vleig  %%v22,4,0  \n\t"
            "vleig  %%v22,5,1  \n\t"
            "vleig  %%v23,6,0  \n\t"
            "vleig  %%v23,7,1  \n\t"
            "vrepig %%v4,8     \n\t"
            "vzero  %%v5       \n\t"
            "vzero  %%v18      \n\t"
            "vzero  %%v19      \n\t"
            ".align 16 \n\t"
            "1: \n\t"
            "pfd 1, 256(%[ptr_tmp] ) \n\t"
            "vlm     %%v24,%%v31, 0(%[ptr_tmp] ) \n\t"
            "vflpdb  %%v24, %%v24 \n\t"
            "vflpdb  %%v25, %%v25 \n\t"
            "vflpdb  %%v26, %%v26 \n\t"
            "vflpdb  %%v27, %%v27 \n\t"
            "vflpdb  %%v28, %%v28 \n\t"
            "vflpdb  %%v29, %%v29 \n\t"
            "vflpdb  %%v30, %%v30 \n\t"
            "vflpdb  %%v31, %%v31 \n\t"
            "vfchdb  %%v16,%%v25,%%v24  \n\t "
            "vfchdb  %%v17,%%v27,%%v26  \n\t "
            "vsel    %%v1,%%v21,%%v20,%%v16 \n\t"
            "vsel    %%v0,%%v25,%%v24,%%v16 \n\t"
            "vsel    %%v2,%%v23,%%v22,%%v17 \n\t"
            "vsel    %%v3,%%v27,%%v26,%%v17 \n\t"
            "vfchdb  %%v16,%%v29,%%v28  \n\t "
            "vfchdb  %%v17,%%v31,%%v30  \n\t"
            "vsel    %%v24,%%v21,%%v20,%%v16 \n\t"
            "vsel    %%v25,%%v29,%%v28,%%v16 \n\t"
            "vsel    %%v26,%%v23,%%v22,%%v17 \n\t"
            "vsel    %%v27,%%v31,%%v30,%%v17 \n\t"

            "vfchdb  %%v28, %%v3,%%v0        \n\t"
            "vfchdb  %%v29,%%v27, %%v25      \n\t"
            "vsel    %%v1,%%v2,%%v1,%%v28    \n\t"
            "vsel    %%v0,%%v3,%%v0,%%v28    \n\t"
            "vsel    %%v24,%%v26,%%v24,%%v29 \n\t"
            "vsel    %%v25,%%v27,%%v25,%%v29 \n\t"
            "vag     %%v1,%%v1,%%v5    \n\t"
            "vag     %%v24,%%v24,%%v5  \n\t"
            "vag     %%v24,%%v24,%%v4  \n\t"
            "vfchdb  %%v16,%%v25 , %%v0      \n\t"
            "vag     %%v5,%%v5,%%v4          \n\t"
            "vsel    %%v29,%%v25,%%v0,%%v16  \n\t"
            "vsel    %%v28,%%v24,%%v1,%%v16  \n\t"
            "vfchdb  %%v17, %%v29,%%v18      \n\t"
            "vsel    %%v19,%%v28,%%v19,%%v17 \n\t"
            "vsel    %%v18,%%v29,%%v18,%%v17 \n\t"
            "vag     %%v5,%%v5,%%v4          \n\t"
            "vlm     %%v24,%%v31,128(%[ptr_tmp] ) \n\t"
            "vflpdb  %%v24, %%v24 \n\t"
            "vflpdb  %%v25, %%v25 \n\t"
            "vflpdb  %%v26, %%v26 \n\t"
            "vflpdb  %%v27, %%v27 \n\t"
            "vflpdb  %%v28, %%v28 \n\t"
            "vflpdb  %%v29, %%v29 \n\t"
            "vflpdb  %%v30, %%v30 \n\t"
            "vflpdb  %%v31, %%v31 \n\t"
            "vfchdb  %%v16,%%v25,%%v24  \n\t "
            "vfchdb  %%v17,%%v27,%%v26  \n\t "
            "vsel    %%v1,%%v21,%%v20,%%v16 \n\t"
            "vsel    %%v0,%%v25,%%v24,%%v16 \n\t"
            "vsel    %%v2,%%v23,%%v22,%%v17 \n\t"
            "vsel    %%v3,%%v27,%%v26,%%v17 \n\t"
            "vfchdb  %%v16,%%v29,%%v28  \n\t "
            "vfchdb  %%v17,%%v31,%%v30  \n\t"
            "vsel    %%v24,%%v21,%%v20,%%v16 \n\t"
            "vsel    %%v25,%%v29,%%v28,%%v16 \n\t"
            "vsel    %%v26,%%v23,%%v22,%%v17 \n\t"
            "vsel    %%v27,%%v31,%%v30,%%v17 \n\t"

            "vfchdb  %%v28, %%v3,%%v0     \n\t"
            "vfchdb  %%v29,%%v27, %%v25   \n\t"
            "vsel    %%v1,%%v2,%%v1,%%v28 \n\t"
            "vsel    %%v0,%%v3,%%v0,%%v28 \n\t"
            "vsel    %%v24,%%v26,%%v24,%%v29 \n\t"
            "vsel    %%v25,%%v27,%%v25,%%v29 \n\t"
            "vag     %%v1,%%v1,%%v5      \n\t"
            "vag     %%v24,%%v24,%%v5    \n\t"
            "la      %[ptr_tmp],256(%[ptr_tmp])   \n\t"
            "vag     %%v24,%%v24,%%v4    \n\t"
            "vfchdb  %%v16,%%v25 , %%v0  \n\t"
            "vag     %%v5,%%v5,%%v4      \n\t"
            "vsel    %%v29,%%v25,%%v0,%%v16  \n\t"
            "vsel    %%v28,%%v24,%%v1,%%v16  \n\t"
            "vfchdb  %%v17, %%v29,%%v18      \n\t"
            "vsel    %%v19,%%v28,%%v19,%%v17 \n\t"
            "vsel    %%v18,%%v29,%%v18,%%v17 \n\t"
            "vag     %%v5,%%v5,%%v4 \n\t"
            "clgrjl  %[ptr_tmp],%%r0,1b  \n\t"

            "vrepg   %%v26,%%v18,1     \n\t"
            "vrepg   %%v5,%%v19,1      \n\t"
            "wfcdb   %%v26,%%v18       \n\t"
            "jne 2f  \n\t"
            "vsteg   %%v18,%[maxf],0   \n\t"
            "vmnlg   %%v1,%%v5,%%v19   \n\t"
            "j 3f    \n\t"

            "2:      \n\t"
            "wfchdb  %%v16,%%v26,%%v18      \n\t"
            "vsel    %%v1,%%v5,%%v19,%%v16  \n\t"
            "vsel    %%v0,%%v26,%%v18,%%v16 \n\t"
            "std     %%f0,%[maxf]           \n\t"
             
            "3:      \n\t"
            "vlgvg   %[index],%%v1,0        \n\t"
            : [index] "+r"(index) ,[maxf] "=m"(*maxf), [ptr_tmp] "+&a"(x)
            : [mem] "m"( *(const double (*)[n])x), [n] "r"(n), [ptr_x] "r"(x) 
            : "cc", "r0", "f0","v0","v1","v2","v3","v4","v5","v6","v7","v16",
            "v17","v18","v19","v20","v21","v22","v23","v24","v25","v26","v27","v28","v29","v30","v31"
            );
    
    return index;

}


 
 
BLASLONG CNAME(BLASLONG n, FLOAT *x, BLASLONG inc_x) {
    BLASLONG i = 0;
    BLASLONG j = 0;
    BLASLONG ix = 0;
    FLOAT maxf = 0.0;
    BLASLONG max = 0;

    if (n <= 0 || inc_x <= 0) return (max);

    if (inc_x == 1) {

        BLASLONG n1 = n & -32;
        if (n1 > 0) {

            max = diamax_kernel_32_TUNED(n1, x, &maxf);

            i = n1;
        }

        while (i < n) {
            if (ABS(x[i]) > maxf) {
                max = i;
                maxf = ABS(x[i]);
            }
            i++;
        }
        return (max + 1);

    } else {

        BLASLONG n1 = n & -4;
        while (j < n1) {

            if (ABS(x[i]) > maxf) {
                max = j;
                maxf = ABS(x[i]);
            }
            if (ABS(x[i + inc_x]) > maxf) {
                max = j + 1;
                maxf = ABS(x[i + inc_x]);
            }
            if (ABS(x[i + 2 * inc_x]) > maxf) {
                max = j + 2;
                maxf = ABS(x[i + 2 * inc_x]);
            }
            if (ABS(x[i + 3 * inc_x]) > maxf) {
                max = j + 3;
                maxf = ABS(x[i + 3 * inc_x]);
            }

            i += inc_x * 4;

            j += 4;

        }


        while (j < n) {
            if (ABS(x[i]) > maxf) {
                max = j;
                maxf = ABS(x[i]);
            }
            i += inc_x;
            j++;
        }
        return (max + 1);
    }
}