OpenBLAS/kernel/riscv64/izamin_rvv.c

/***************************************************************************
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*****************************************************************************/

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

#if defined(DOUBLE)
#define VSETVL(n)               __riscv_vsetvl_e64m4(n)
#define VSETVL_MAX              __riscv_vsetvlmax_e64m4()
#define FLOAT_V_T               vfloat64m4_t
#define FLOAT_V_T_M1            vfloat64m1_t
#define VLSEG_FLOAT             __riscv_vlseg2e64_v_f64m4
#define VLSSEG_FLOAT            __riscv_vlsseg2e64_v_f64m4
#define VFREDMINVS_FLOAT        __riscv_vfredmin_vs_f64m4_f64m1
#define MASK_T                  vbool16_t
#define VMFLTVF_FLOAT           __riscv_vmflt_vf_f64m4_b16
#define VMFLTVV_FLOAT           __riscv_vmflt_vv_f64m4_b16
#define VMFLEVF_FLOAT           __riscv_vmfle_vf_f64m4_b16
#define VFMVVF_FLOAT            __riscv_vfmv_v_f_f64m4
#define VFMVVF_FLOAT_M1         __riscv_vfmv_v_f_f64m1
#define VFABSV_FLOAT            __riscv_vfabs_v_f64m4
#define VFMINVV_FLOAT_TU        __riscv_vfmin_vv_f64m4_tu
#define VFADDVV_FLOAT           __riscv_vfadd_vv_f64m4
#define VFIRSTM                 __riscv_vfirst_m_b16
#define UINT_V_T                vuint64m4_t
#define VIDV_MASK_UINT_TU       __riscv_vid_v_u64m4_tumu
#define VIDV_UINT               __riscv_vid_v_u64m4
#define VADDVX_MASK_UINT_TU     __riscv_vadd_vx_u64m4_tumu
#define VADDVX_UINT             __riscv_vadd_vx_u64m4
#define VMVVX_UINT              __riscv_vmv_v_x_u64m4
#define VFMVFS_FLOAT_M1         __riscv_vfmv_f_s_f64m1_f64
#define VSLIDEDOWN_UINT         __riscv_vslidedown_vx_u64m4
#define VMVVXS_UINT             __riscv_vmv_x_s_u64m4_u64
#else
#define VSETVL(n)               __riscv_vsetvl_e32m4(n)
#define VSETVL_MAX              __riscv_vsetvlmax_e32m4()
#define FLOAT_V_T               vfloat32m4_t
#define FLOAT_V_T_M1            vfloat32m1_t
#define VLSEG_FLOAT             __riscv_vlseg2e32_v_f32m4
#define VLSSEG_FLOAT            __riscv_vlsseg2e32_v_f32m4
#define VFREDMINVS_FLOAT        __riscv_vfredmin_vs_f32m4_f32m1
#define MASK_T                  vbool8_t
#define VMFLTVF_FLOAT           __riscv_vmflt_vf_f32m4_b8
#define VMFLTVV_FLOAT           __riscv_vmflt_vv_f32m4_b8
#define VMFLEVF_FLOAT           __riscv_vmfle_vf_f32m4_b8
#define VFMVVF_FLOAT            __riscv_vfmv_v_f_f32m4
#define VFMVVF_FLOAT_M1         __riscv_vfmv_v_f_f32m1
#define VFABSV_FLOAT            __riscv_vfabs_v_f32m4
#define VFMINVV_FLOAT_TU        __riscv_vfmin_vv_f32m4_tu
#define VFADDVV_FLOAT           __riscv_vfadd_vv_f32m4
#define VFIRSTM                 __riscv_vfirst_m_b8
#define UINT_V_T                vuint32m4_t
#define VIDV_MASK_UINT_TU       __riscv_vid_v_u32m4_tumu
#define VIDV_UINT               __riscv_vid_v_u32m4
#define VADDVX_MASK_UINT_TU     __riscv_vadd_vx_u32m4_tumu
#define VADDVX_UINT             __riscv_vadd_vx_u32m4
#define VMVVX_UINT              __riscv_vmv_v_x_u32m4
#define VFMVFS_FLOAT_M1         __riscv_vfmv_f_s_f32m1_f32
#define VSLIDEDOWN_UINT         __riscv_vslidedown_vx_u32m4
#define VMVVXS_UINT             __riscv_vmv_x_s_u32m4_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 vx0, vx1, 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*2, j += vl) {
            vl = VSETVL(n);

            VLSEG_FLOAT(&vx0, &vx1, x, vl);

            vx0 = VFABSV_FLOAT(vx0, vl);
            vx1 = VFABSV_FLOAT(vx1, vl);

            vx0 = VFADDVV_FLOAT(vx0, vx1, vl);

            // index where element less than v_min
            mask = VMFLTVV_FLOAT(vx0, v_min, vl);
            v_min_index = VIDV_MASK_UINT_TU(mask, v_min_index, vl);
            v_min_index = VADDVX_MASK_UINT_TU(mask, v_min_index, v_min_index, j, vl);

            //update v_min and start_index j
            v_min = VFMINVV_FLOAT_TU(v_min, v_min, vx0, vl);
        }

    } else {

        BLASLONG stride_x = inc_x * sizeof(FLOAT) * 2;

        for (size_t vl; n > 0; n -= vl, x += vl*inc_x*2, j += vl) {
            vl = VSETVL(n);

            VLSSEG_FLOAT(&vx0, &vx1, x, stride_x, vl);

            vx0 = VFABSV_FLOAT(vx0, vl);
            vx1 = VFABSV_FLOAT(vx1, vl);

            vx0 = VFADDVV_FLOAT(vx0, vx1, vl);

            // index where element less than v_min
            mask = VMFLTVV_FLOAT(vx0, v_min, vl);
            v_min_index = VIDV_MASK_UINT_TU(mask, v_min_index, vl);
            v_min_index = VADDVX_MASK_UINT_TU(mask, v_min_index, v_min_index, j, vl);

            //update v_min and start_index j
            v_min = VFMINVV_FLOAT_TU(v_min, v_min, vx0, vl);
        }

    }

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

    v_res = VFREDMINVS_FLOAT(v_min, v_res, 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, min_index, vlmax);
    min_index = VMVVXS_UINT(v_min_index);

    return(min_index+1);
}