OpenBLAS/kernel/riscv64/imin_rvv.c

/***************************************************************************
Copyright (c) 2022, The OpenBLAS Project
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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
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ARE DISCLAIMED. IN NO EVENT SHALL THE OPENBLAS PROJECT OR CONTRIBUTORS BE
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*****************************************************************************/

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

#if defined(DOUBLE)
#define VSETVL(n) vsetvl_e64m8(n)
#define VSETVL_MAX vsetvlmax_e64m8()
#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 VFREDMINVS_FLOAT vfredmin_vs_f64m8_f64m1
#define MASK_T vbool8_t
#define VMFLTVF_FLOAT vmflt_vf_f64m8_b8
#define VMFLTVV_FLOAT vmflt_vv_f64m8_b8
#define VMFLEVF_FLOAT vmfle_vf_f64m8_b8
#define VFMVVF_FLOAT vfmv_v_f_f64m8
#define VFMVVF_FLOAT_M1 vfmv_v_f_f64m1
#define VFMINVV_FLOAT vfmin_vv_f64m8
#define VFIRSTM vfirst_m_b8
#define UINT_V_T vuint64m8_t
#define VIDV_MASK_UINT vid_v_u64m8_m
#define VIDV_UINT vid_v_u64m8
#define VADDVX_MASK_UINT vadd_vx_u64m8_m
#define VADDVX_UINT vadd_vx_u64m8
#define VMVVX_UINT vmv_v_x_u64m8
#define VFMVFS_FLOAT_M1 vfmv_f_s_f64m1_f64
#define VSLIDEDOWN_UINT vslidedown_vx_u64m8
#define VMVVXS_UINT vmv_x_s_u64m8_u64
#else
#define VSETVL(n) vsetvl_e32m8(n)
#define VSETVL_MAX vsetvlmax_e32m8()
#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 VFREDMINVS_FLOAT vfredmin_vs_f32m8_f32m1
#define MASK_T vbool4_t
#define VMFLTVF_FLOAT vmflt_vf_f32m8_b4
#define VMFLTVV_FLOAT vmflt_vv_f32m8_b4
#define VMFLEVF_FLOAT vmfle_vf_f32m8_b4
#define VFMVVF_FLOAT vfmv_v_f_f32m8
#define VFMVVF_FLOAT_M1 vfmv_v_f_f32m1
#define VFMINVV_FLOAT vfmin_vv_f32m8
#define VFIRSTM vfirst_m_b4
#define UINT_V_T vuint32m8_t
#define VIDV_MASK_UINT vid_v_u32m8_m
#define VIDV_UINT vid_v_u32m8
#define VADDVX_MASK_UINT vadd_vx_u32m8_m
#define VADDVX_UINT vadd_vx_u32m8
#define VMVVX_UINT vmv_v_x_u32m8
#define VFMVFS_FLOAT_M1 vfmv_f_s_f32m1_f32
#define VSLIDEDOWN_UINT vslidedown_vx_u32m8
#define VMVVXS_UINT vmv_x_s_u32m8_u32
#endif

BLASLONG CNAME(BLASLONG n, FLOAT *x, BLASLONG inc_x)
{
    unsigned int min_index = 0;
    if (n <= 0 || inc_x <= 0) return(min_index);

    FLOAT_V_T vx, v_min;
    UINT_V_T v_min_index;
    MASK_T mask;
  
    size_t vlmax = VSETVL_MAX;
    v_min_index = VMVVX_UINT(0, vlmax);
    v_min = VFMVVF_FLOAT(FLT_MAX, vlmax);
    BLASLONG j=0;
    FLOAT minf=0.0;
    
    if(inc_x == 1) {

        for (size_t vl; n > 0; n -= vl, x += vl, j += vl) {
            vl = VSETVL(n);

            vx = VLEV_FLOAT(x, vl);

            // index where element less than v_min
            mask = VMFLTVV_FLOAT(vx, v_min, vl);
            v_min_index = VIDV_MASK_UINT(mask, v_min_index, vl);
            v_min_index = VADDVX_MASK_UINT(mask, v_min_index, v_min_index, j, vl);

            //update v_min and start_index j
            v_min = VFMINVV_FLOAT(v_min, vx, vl);
        }

    } else {
  
        BLASLONG stride_x = inc_x * sizeof(FLOAT);

        for (size_t vl; n > 0; n -= vl, x += vl*inc_x, j += vl) {
            vl = VSETVL(n);

            vx = VLSEV_FLOAT(x, stride_x, vl);

            // index where element less than v_min
            mask = VMFLTVV_FLOAT(vx, v_min, vl);
            v_min_index = VIDV_MASK_UINT(mask, v_min_index, vl);
            v_min_index = VADDVX_MASK_UINT(mask, v_min_index, v_min_index, j, vl);

            //update v_min and start_index j
            v_min = VFMINVV_FLOAT(v_min, vx, vl);
        }
  
    }

    FLOAT_V_T_M1 v_res, v_max;
    v_res = VFMVVF_FLOAT_M1(0, vlmax);
    v_max = VFMVVF_FLOAT_M1(FLT_MAX, vlmax);

    v_res = VFREDMINVS_FLOAT(v_res, v_min, v_max, vlmax);
    minf = VFMVFS_FLOAT_M1(v_res);
    mask = VMFLEVF_FLOAT(v_min, minf, vlmax);
    min_index = VFIRSTM(mask, vlmax);

    v_min_index = VSLIDEDOWN_UINT(v_min_index, v_min_index, min_index, vlmax);
    min_index = VMVVXS_UINT(v_min_index);

    return(min_index+1);
}