OpenBLAS/kernel/zarch/camax.c

/***************************************************************************
Copyright (c) 2013-2017, The OpenBLAS Project
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*****************************************************************************/

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

#if defined(DOUBLE)
#define ABS fabs
#else
#define ABS fabsf
#endif

#define CABS1(x,i) (ABS(x[i]) + ABS(x[i + 1]))

static FLOAT camax_kernel_32(BLASLONG n, FLOAT *x)
{
    FLOAT amax;

    __asm__ volatile (
        "vlef   %%v0,0(%2),0              \n\t"
        "vlef   %%v16,4(%2),0             \n\t"
        "vlef   %%v0,8(%2),1              \n\t"
        "vlef   %%v16,12(%2),1            \n\t"
        "vlef   %%v0,16(%2),2             \n\t"
        "vlef   %%v16,20(%2),2            \n\t"
        "vlef   %%v0,24(%2),3             \n\t"
        "vlef   %%v16,28(%2),3            \n\t"
        "vflpsb %%v0,%%v0                 \n\t"
        "vflpsb %%v16,%%v16               \n\t"
        "vfasb  %%v0,%%v0,%%v16           \n\t"
        "vleib  %%v1,0,0                  \n\t"
        "vleib  %%v1,1,1                  \n\t"
        "vleib  %%v1,2,2                  \n\t"
        "vleib  %%v1,3,3                  \n\t"
        "vleib  %%v1,8,4                  \n\t"
        "vleib  %%v1,9,5                  \n\t"
        "vleib  %%v1,10,6                 \n\t"
        "vleib  %%v1,11,7                 \n\t"
        "vleib  %%v1,16,8                 \n\t"
        "vleib  %%v1,17,9                 \n\t"
        "vleib  %%v1,18,10                \n\t"
        "vleib  %%v1,19,11                \n\t"
        "vleib  %%v1,24,12                \n\t"
        "vleib  %%v1,25,13                \n\t"
        "vleib  %%v1,26,14                \n\t"
        "vleib  %%v1,27,15                \n\t"
        "srlg  %%r0,%1,5                  \n\t"
        "xgr %%r1,%%r1                    \n\t"
        "0:                               \n\t"
        "pfd 1, 1024(%%r1,%2)             \n\t"

        "vl    %%v16,0(%%r1,%2)           \n\t"
        "vl    %%v2,16(%%r1,%2)           \n\t"
        "vpkg  %%v17,%%v16,%%v2           \n\t"
        "vperm %%v16,%%v16,%%v2,%%v1      \n\t"

        "vl    %%v18,32(%%r1,%2)          \n\t"
        "vl    %%v2,48(%%r1,%2)           \n\t"
        "vpkg  %%v19,%%v18,%%v2           \n\t"
        "vperm %%v18,%%v18,%%v2,%%v1      \n\t"

        "vl    %%v20,64(%%r1,%2)          \n\t"
        "vl    %%v2,80(%%r1,%2)           \n\t"
        "vpkg  %%v21,%%v20,%%v2           \n\t"
        "vperm %%v20,%%v20,%%v2,%%v1      \n\t"

        "vl    %%v22,96(%%r1,%2)          \n\t"
        "vl    %%v2,112(%%r1,%2)          \n\t"
        "vpkg  %%v23,%%v22,%%v2           \n\t"
        "vperm %%v22,%%v22,%%v2,%%v1      \n\t"

        "vl    %%v24,128(%%r1,%2)         \n\t"
        "vl    %%v2,144(%%r1,%2)          \n\t"
        "vpkg  %%v25,%%v24,%%v2           \n\t"
        "vperm %%v24,%%v24,%%v2,%%v1      \n\t"

        "vl    %%v26,160(%%r1,%2)         \n\t"
        "vl    %%v2,176(%%r1,%2)          \n\t"
        "vpkg  %%v27,%%v26,%%v2           \n\t"
        "vperm %%v26,%%v26,%%v2,%%v1      \n\t"

        "vl    %%v28,192(%%r1,%2)         \n\t"
        "vl    %%v2,208(%%r1,%2)          \n\t"
        "vpkg  %%v29,%%v28,%%v2           \n\t"
        "vperm %%v28,%%v28,%%v2,%%v1      \n\t"

        "vl    %%v30,224(%%r1,%2)         \n\t"
        "vl    %%v2,240(%%r1,%2)          \n\t"
        "vpkg  %%v31,%%v30,%%v2           \n\t"
        "vperm %%v30,%%v30,%%v2,%%v1      \n\t"

        "vflpsb  %%v16,%%v16              \n\t"
        "vflpsb  %%v17,%%v17              \n\t"
        "vflpsb  %%v18,%%v18              \n\t"
        "vflpsb  %%v19,%%v19              \n\t"
        "vflpsb  %%v20,%%v20              \n\t"
        "vflpsb  %%v21,%%v21              \n\t"
        "vflpsb  %%v22,%%v22              \n\t"
        "vflpsb  %%v23,%%v23              \n\t"
        "vflpsb  %%v24,%%v24              \n\t"
        "vflpsb  %%v25,%%v25              \n\t"
        "vflpsb  %%v26,%%v26              \n\t"
        "vflpsb  %%v27,%%v27              \n\t"
        "vflpsb  %%v28,%%v28              \n\t"
        "vflpsb  %%v29,%%v29              \n\t"
        "vflpsb  %%v30,%%v30              \n\t"
        "vflpsb  %%v31,%%v31              \n\t"

        "vfasb %%v16,%%v16,%%v17          \n\t"
        "vfasb %%v18,%%v18,%%v19          \n\t"
        "vfasb %%v20,%%v20,%%v21          \n\t"
        "vfasb %%v22,%%v22,%%v23          \n\t"
        "vfasb %%v24,%%v24,%%v25          \n\t"
        "vfasb %%v26,%%v26,%%v27          \n\t"
        "vfasb %%v28,%%v28,%%v29          \n\t"
        "vfasb %%v30,%%v30,%%v31          \n\t"
        
        "vfmaxsb  %%v16,%%v16,%%v24,0     \n\t"
        "vfmaxsb  %%v18,%%v18,%%v26,0     \n\t"
        "vfmaxsb  %%v20,%%v20,%%v28,0     \n\t"
        "vfmaxsb  %%v22,%%v22,%%v30,0     \n\t"

        "vfmaxsb  %%v16,%%v16,%%v20,0     \n\t"
        "vfmaxsb  %%v18,%%v18,%%v22,0     \n\t"

        "vfmaxsb  %%v16,%%v16,%%v18,0     \n\t"

        "vfmaxsb  %%v0,%%v0,%%v16,0       \n\t"

        "agfi    %%r1, 256                \n\t"
        "brctg   %%r0, 0b                 \n\t"

        "veslg   %%v16,%%v0,32            \n\t"
        "vfmaxsb %%v0,%%v0,%%v16,0        \n\t"

        "vrepf  %%v16,%%v0,2              \n\t"
        "wfmaxsb %%v0,%%v0,%%v16,0        \n\t"
        "ler    %0,%%f0                       "
        :"=f"(amax)
        :"r"(n),"ZR"((const FLOAT (*)[n])x)
        :"memory","cc","r0","r1","v0","v1","v2","v16","v17","v18","v19","v20","v21","v22","v23","v24","v25","v26","v27","v28","v29","v30","v31"
    );

    return amax;
}
 
FLOAT CNAME(BLASLONG n, FLOAT *x, BLASLONG inc_x) {
    BLASLONG i = 0;
    BLASLONG ix = 0;
    FLOAT maxf = 0.0;
    BLASLONG inc_x2;

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

    if (inc_x == 1) {

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

            maxf = camax_kernel_32(n1, x);
            ix = n1 * 2;
            i = n1;
        }
        else
        {
            maxf=CABS1(x,0);
            ix += 2;
            i++;
        }

        while (i < n) {
            if (CABS1(x,ix) > maxf) {
                maxf = CABS1(x,ix);
            }
            ix += 2;
            i++;
        }
        return (maxf);

    } else {

        maxf=CABS1(x,0);
        inc_x2 = 2 * inc_x;

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

            if (CABS1(x,ix) > maxf) {
                maxf = CABS1(x,ix);
            }
            if (CABS1(x,ix+inc_x2) > maxf) {
                maxf = CABS1(x,ix+inc_x2);
            }
            if (CABS1(x,ix+inc_x2*2) > maxf) {
                maxf = CABS1(x,ix+inc_x2*2);
            }
            if (CABS1(x,ix+inc_x2*3) > maxf) {
                maxf = CABS1(x,ix+inc_x2*3);
            }

            ix += inc_x2 * 4;

            i += 4;

        }


        while (i < n) {
            if (CABS1(x,ix) > maxf) {
                maxf = CABS1(x,ix);
            }
            ix += inc_x2;
            i++;
        }
        return (maxf);
    }
}