OpenBLAS/kernel/riscv64/imax_vector.c

/***************************************************************************
Copyright (c) 2020, The OpenBLAS Project
All rights reserved.
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modification, are permitted provided that the following conditions are
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its contributors may be used to endorse or promote products
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE OPENBLAS PROJECT OR CONTRIBUTORS BE
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*****************************************************************************/

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

#if defined(DOUBLE)

#define ABS fabs
#define RVV_EFLOAT RVV_E64
#define RVV_M RVV_M8
#define FLOAT_V_T float64xm8_t
#define VLEV_FLOAT vlev_float64xm8
#define VLSEV_FLOAT vlsev_float64xm8
#define VFREDMAXVS_FLOAT vfredmaxvs_float64xm8
#define MASK_T e64xm8_t
#define VMFLTVV_FLOAT vmfltvv_e64xm8_float64xm8
#define VFMVVF_FLOAT vfmvvf_float64xm8
#define VFMAXVV_FLOAT vfmaxvv_float64xm8
#define VMFGEVF_FLOAT vmfgevf_e64xm8_float64xm8
#define VMFIRSTM vmfirstm_e64xm8
#define UINT_V_T uint64xm8_t
#define VIDV_MASK_UINT vidv_mask_uint64xm8
#define VIDV_UINT vidv_uint64xm8
#define VADDVX_MASK_UINT vaddvx_mask_uint64xm8
#define VADDVX_UINT vaddvx_uint64xm8
#define VMVVX_UINT vmvvx_uint64xm8
#else

#define ABS fabsf
#define RVV_EFLOAT RVV_E32
#define RVV_M RVV_M8
#define FLOAT_V_T float32xm8_t
#define VLEV_FLOAT vlev_float32xm8
#define VLSEV_FLOAT vlsev_float32xm8
#define VFREDMAXVS_FLOAT vfredmaxvs_float32xm8
#define MASK_T e32xm8_t
#define VMFLTVV_FLOAT vmfltvv_e32xm8_float32xm8
#define VFMVVF_FLOAT vfmvvf_float32xm8
#define VFMAXVV_FLOAT vfmaxvv_float32xm8
#define VMFGEVF_FLOAT vmfgevf_e32xm8_float32xm8
#define VMFIRSTM vmfirstm_e32xm8
#define UINT_V_T uint32xm8_t
#define VIDV_MASK_UINT vidv_mask_uint32xm8
#define VIDV_UINT vidv_uint32xm8
#define VADDVX_MASK_UINT vaddvx_mask_uint32xm8
#define VADDVX_UINT vaddvx_uint32xm8
#define VMVVX_UINT vmvvx_uint32xm8
#endif


BLASLONG CNAME(BLASLONG n, FLOAT *x, BLASLONG inc_x)
{
	BLASLONG i=0, j=0;
        unsigned int max_index = 0;
	if (n <= 0 || inc_x <= 0) return(max_index);
	FLOAT maxf=-FLT_MAX;

        FLOAT_V_T vx, v_max;
        UINT_V_T v_max_index;
        MASK_T mask;
        unsigned int gvl = 0;
        if(inc_x == 1){
                gvl = vsetvli(n, RVV_EFLOAT, RVV_M);
                v_max_index = VMVVX_UINT(0, gvl);
                v_max = VFMVVF_FLOAT(-FLT_MAX, gvl);
                for(i=0,j=0; i < n/gvl; i++){
                        vx = VLEV_FLOAT(&x[j], gvl);

                        //index where element greater than v_max
                        mask = VMFLTVV_FLOAT(v_max, vx, gvl);
                        v_max_index = VIDV_MASK_UINT(v_max_index, mask, gvl);
                        v_max_index = VADDVX_MASK_UINT(v_max_index, v_max_index, j, mask, gvl);

                        //update v_max and start_index j
                        v_max = VFMAXVV_FLOAT(v_max, vx, gvl);
                        j += gvl;
                }
                vx = VFMVVF_FLOAT(-FLT_MAX, gvl);
                vx = VFREDMAXVS_FLOAT(v_max, vx, gvl);
                maxf = vx[0];
                mask = VMFGEVF_FLOAT(v_max, maxf, gvl);
                max_index = VMFIRSTM(mask,gvl);
                max_index = v_max_index[max_index];

                if(j < n){
                        gvl = vsetvli(n-j, RVV_EFLOAT, RVV_M);
                        v_max = VLEV_FLOAT(&x[j], gvl);

                        vx = VFMVVF_FLOAT(-FLT_MAX, gvl);
                        vx = VFREDMAXVS_FLOAT(v_max, vx, gvl);
                        FLOAT cur_maxf = vx[0];
                        if(cur_maxf > maxf){
                                //tail index
                                v_max_index = VIDV_UINT(gvl);
                                v_max_index = VADDVX_UINT(v_max_index, j, gvl);

                                mask = VMFGEVF_FLOAT(v_max, cur_maxf, gvl);
                                max_index = VMFIRSTM(mask,gvl);
                                max_index = v_max_index[max_index];
                        }
                }
        }else{
                gvl = vsetvli(n, RVV_EFLOAT, RVV_M);
                unsigned int stride_x = inc_x * sizeof(FLOAT);
                unsigned int idx = 0, inc_v = gvl * inc_x;

                v_max = VFMVVF_FLOAT(-FLT_MAX, gvl);
                v_max_index = VMVVX_UINT(0, gvl);
                for(i=0,j=0; i < n/gvl; i++){
                        vx = VLSEV_FLOAT(&x[idx], stride_x, gvl);

                        //index where element greater than v_max
                        mask = VMFLTVV_FLOAT(v_max, vx, gvl);
                        v_max_index = VIDV_MASK_UINT(v_max_index, mask, gvl);
                        v_max_index = VADDVX_MASK_UINT(v_max_index, v_max_index, j, mask, gvl);

                        //update v_max and start_index j
                        v_max = VFMAXVV_FLOAT(v_max, vx, gvl);
                        j += gvl;
                        idx += inc_v;
                }
                vx = VFMVVF_FLOAT(-FLT_MAX, gvl);
                vx = VFREDMAXVS_FLOAT(v_max, vx, gvl);
                maxf = vx[0];
                mask = VMFGEVF_FLOAT(v_max, maxf, gvl);
                max_index = VMFIRSTM(mask,gvl);
                max_index = v_max_index[max_index];

                if(j < n){
                        gvl = vsetvli(n-j, RVV_EFLOAT, RVV_M);
                        v_max = VLSEV_FLOAT(&x[idx], stride_x, gvl);

                        vx = VFMVVF_FLOAT(-FLT_MAX, gvl);
                        vx = VFREDMAXVS_FLOAT(v_max, vx, gvl);
                        FLOAT cur_maxf = vx[0];
                        if(cur_maxf > maxf){
                                //tail index
                                v_max_index = VIDV_UINT(gvl);
                                v_max_index = VADDVX_UINT(v_max_index, j, gvl);

                                mask = VMFGEVF_FLOAT(v_max, cur_maxf, gvl);
                                max_index = VMFIRSTM(mask,gvl);
                                max_index = v_max_index[max_index];
                        }
                }
        }
	return(max_index+1);
}