OpenBLAS/kernel/riscv64/max_vector.c

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#include "common.h"
#include <math.h>
#include <float.h>
#if !defined(DOUBLE)
#define VSETVL(n) vsetvl_e32m8(n)
#define VSETVL_MAX vsetvlmax_e32m1()
#define FLOAT_V_T vfloat32m8_t
#define FLOAT_V_T_M1 vfloat32m1_t
#define VLEV_FLOAT vle32_v_f32m8
#define VLSEV_FLOAT vlse32_v_f32m8
#define VFREDMAXVS_FLOAT vfredmax_vs_f32m8_f32m1
#define VFMVVF_FLOAT vfmv_v_f_f32m8
#define VFMVVF_FLOAT_M1 vfmv_v_f_f32m1
#define VFMAXVV_FLOAT vfmax_vv_f32m8
#else
#define VSETVL(n) vsetvl_e64m8(n)
#define VSETVL_MAX vsetvlmax_e64m1()
#define FLOAT_V_T vfloat64m8_t
#define FLOAT_V_T_M1 vfloat64m1_t
#define VLEV_FLOAT vle64_v_f64m8
#define VLSEV_FLOAT vlse64_v_f64m8
#define VFREDMAXVS_FLOAT vfredmax_vs_f64m8_f64m1
#define VFMVVF_FLOAT vfmv_v_f_f64m8
#define VFMVVF_FLOAT_M1 vfmv_v_f_f64m1
#define VFMAXVV_FLOAT vfmax_vv_f64m8
#endif

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_min;
        gvl = VSETVL_MAX;
        v_res = VFMVVF_FLOAT_M1(0, gvl);
        v_min = VFMVVF_FLOAT_M1(-FLT_MAX, gvl);

        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_res, v_max, v_min, gvl);
                        maxf = *((FLOAT*)&v_res);
                }
                for(;j<n;){
                        gvl = VSETVL(n-j);
                        v0 = VLEV_FLOAT(&x[j], gvl);
                        v_res = VFREDMAXVS_FLOAT(v_res, v0, v_min, gvl);
                        if(*((FLOAT*)&v_res) > maxf)
                                maxf = *((FLOAT*)&v_res);
                        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_res, v_max, v_min, gvl);
                        maxf = *((FLOAT*)&v_res);
                }
                for(;j<n;){
                        gvl = VSETVL(n-j);
                        v0 = VLSEV_FLOAT(&x[j*inc_x], stride_x, gvl);
                        v_res = VFREDMAXVS_FLOAT(v_res, v0, v_min, gvl);
                        if(*((FLOAT*)&v_res) > maxf)
                                maxf = *((FLOAT*)&v_res);
                        j += gvl;
                }
        }
	return(maxf);
}