OpenBLAS/kernel/riscv64/max_vector.c

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

#ifdef RISCV64_ZVL256B
#       define LMUL m2
#       if defined(DOUBLE)
#               define ELEN 64
#               define MLEN 32
#       else
#               define ELEN 32
#               define MLEN 16
#       endif
#else
#       define LMUL m8
#       if defined(DOUBLE)
#               define ELEN 64
#               define MLEN 8
#       else
#               define ELEN 32
#               define MLEN 4
#       endif
#endif

#define _
#define JOIN2_X(x, y) x ## y
#define JOIN2(x, y) JOIN2_X(x, y)
#define JOIN(v, w, x, y, z) JOIN2( JOIN2( JOIN2( JOIN2( v, w ), x), y), z)

#define VSETVL          JOIN(RISCV_RVV(vsetvl),    _e,     ELEN,   LMUL,   _)
#define FLOAT_V_T       JOIN(vfloat,            ELEN,   LMUL,   _t,     _)
#define FLOAT_V_T_M1    JOIN(vfloat,            ELEN,   m1,     _t,     _)
#define VLEV_FLOAT      JOIN(RISCV_RVV(vle),       ELEN,   _v_f,   ELEN,   LMUL)
#define VLSEV_FLOAT     JOIN(RISCV_RVV(vlse),      ELEN,   _v_f,   ELEN,   LMUL)
#ifdef RISCV_0p10_INTRINSICS
#define VFREDMAXVS_FLOAT(va, vb, gvl) JOIN(RISCV_RVV(vfredmax_vs_f),  ELEN,   LMUL,   _f, JOIN2( ELEN,   m1))(v_res, va, vb, gvl)
#else
#define VFREDMAXVS_FLOAT JOIN(RISCV_RVV(vfredmax_vs_f),  ELEN,   LMUL,   _f, JOIN2( ELEN,   m1))
#endif
#define MASK_T          JOIN(vbool,     MLEN,   _t,     _,      _)
#define VMFLTVF_FLOAT   JOIN(RISCV_RVV(vmflt_vf_f), ELEN,  LMUL,   _b,     MLEN)
#define VFMVVF_FLOAT    JOIN(RISCV_RVV(vfmv),      _v_f_f, ELEN,   LMUL,   _)
#define VFMVVF_FLOAT_M1 JOIN(RISCV_RVV(vfmv),      _v_f_f, ELEN,   m1,     _)
#define VFMAXVV_FLOAT   JOIN(RISCV_RVV(vfmax),     _vv_f,  ELEN,   LMUL,   _)

FLOAT CNAME(BLASLONG n, FLOAT *x, BLASLONG inc_x)
{
	BLASLONG i=0, j=0;
	if (n <= 0 || inc_x <= 0) return(0.0);
	FLOAT maxf=-FLT_MAX;
        unsigned int gvl = 0;
        FLOAT_V_T v0, v1, v_max;
        FLOAT_V_T_M1 v_res;
        v_res = VFMVVF_FLOAT_M1(-FLT_MAX, 1);

        if(inc_x == 1){
                gvl = VSETVL(n);
                if(gvl <= n/2){
                        v_max = VFMVVF_FLOAT(-FLT_MAX, gvl);
                        for(i=0,j=0; i<n/(gvl*2); i++){
                                v0 = VLEV_FLOAT(&x[j], gvl);
                                v_max = VFMAXVV_FLOAT(v_max, v0, gvl);

                                v1 = VLEV_FLOAT(&x[j+gvl], gvl);
                                v_max = VFMAXVV_FLOAT(v_max, v1, gvl);
                                j += gvl * 2;
                        }
                        v_res = VFREDMAXVS_FLOAT(v_max, v_res, gvl);
                }
                for(;j<n;){
                        gvl = VSETVL(n-j);
                        v0 = VLEV_FLOAT(&x[j], gvl);
                        v_res = VFREDMAXVS_FLOAT(v0, v_res, gvl);
                        j += gvl;
                }
        }else{
                gvl = VSETVL(n);
                BLASLONG stride_x = inc_x * sizeof(FLOAT);
                if(gvl <= n/2){
                        v_max = VFMVVF_FLOAT(-FLT_MAX, gvl);
                        BLASLONG idx = 0, inc_xv = inc_x * gvl;
                        for(i=0,j=0; i<n/(gvl*2); i++){
                                v0 = VLSEV_FLOAT(&x[idx], stride_x, gvl);
                                v_max = VFMAXVV_FLOAT(v_max, v0, gvl);

                                v1 = VLSEV_FLOAT(&x[idx+inc_xv], stride_x, gvl);
                                v_max = VFMAXVV_FLOAT(v_max, v1, gvl);
                                j += gvl * 2;
                                idx += inc_xv * 2;
                        }
                        v_res = VFREDMAXVS_FLOAT(v_max, v_res, gvl);
                }
                for(;j<n;){
                        gvl = VSETVL(n-j);
                        v0 = VLSEV_FLOAT(&x[j*inc_x], stride_x, gvl);
                        v_res = VFREDMAXVS_FLOAT(v0, v_res, gvl);
                        j += gvl;
                }
        }
        maxf = EXTRACT_FLOAT(v_res);
	return(maxf);
}