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

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

#if defined(DOUBLE)
#define VSETVL(n)               __riscv_vsetvl_e64m8(n)
#define VSETVL_MAX              __riscv_vsetvlmax_e64m8()
#define FLOAT_V_T               vfloat64m8_t
#define FLOAT_V_T_M1            vfloat64m1_t
#define VLEV_FLOAT              __riscv_vle64_v_f64m8
#define VLSEV_FLOAT             __riscv_vlse64_v_f64m8
#define VFREDMAXVS_FLOAT        __riscv_vfredmax_vs_f64m8_f64m1
#define MASK_T                  vbool8_t
#define VMFLTVF_FLOAT           __riscv_vmflt_vf_f64m8_b8
#define VMFLTVV_FLOAT           __riscv_vmflt_vv_f64m8_b8
#define VMFGEVF_FLOAT           __riscv_vmfge_vf_f64m8_b8
#define VFMVVF_FLOAT            __riscv_vfmv_v_f_f64m8
#define VFMVVF_FLOAT_M1         __riscv_vfmv_v_f_f64m1
#define VFMAXVV_FLOAT_TU        __riscv_vfmax_vv_f64m8_tu
#define VFIRSTM                 __riscv_vfirst_m_b8
#define UINT_V_T                vuint64m8_t
#define VIDV_MASK_UINT_TU       __riscv_vid_v_u64m8_tumu
#define VIDV_UINT               __riscv_vid_v_u64m8
#define VADDVX_MASK_UINT_TU     __riscv_vadd_vx_u64m8_tumu
#define VADDVX_UINT             __riscv_vadd_vx_u64m8
#define VMVVX_UINT              __riscv_vmv_v_x_u64m8
#define VFMVFS_FLOAT_M1         __riscv_vfmv_f_s_f64m1_f64
#define VSLIDEDOWN_UINT         __riscv_vslidedown_vx_u64m8
#define VMVVXS_UINT             __riscv_vmv_x_s_u64m8_u64
#else
#define VSETVL(n)               __riscv_vsetvl_e32m8(n)
#define VSETVL_MAX              __riscv_vsetvlmax_e32m8()
#define FLOAT_V_T               vfloat32m8_t
#define FLOAT_V_T_M1            vfloat32m1_t
#define VLEV_FLOAT              __riscv_vle32_v_f32m8
#define VLSEV_FLOAT             __riscv_vlse32_v_f32m8
#define VFREDMAXVS_FLOAT        __riscv_vfredmax_vs_f32m8_f32m1
#define MASK_T                  vbool4_t
#define VMFLTVF_FLOAT           __riscv_vmflt_vf_f32m8_b4
#define VMFLTVV_FLOAT           __riscv_vmflt_vv_f32m8_b4
#define VMFGEVF_FLOAT           __riscv_vmfge_vf_f32m8_b4
#define VFMVVF_FLOAT            __riscv_vfmv_v_f_f32m8
#define VFMVVF_FLOAT_M1         __riscv_vfmv_v_f_f32m1
#define VFMAXVV_FLOAT_TU        __riscv_vfmax_vv_f32m8_tu
#define VFIRSTM                 __riscv_vfirst_m_b4
#define UINT_V_T                vuint32m8_t
#define VIDV_MASK_UINT_TU       __riscv_vid_v_u32m8_tumu
#define VIDV_UINT               __riscv_vid_v_u32m8
#define VADDVX_MASK_UINT_TU     __riscv_vadd_vx_u32m8_tumu
#define VADDVX_UINT             __riscv_vadd_vx_u32m8
#define VMVVX_UINT              __riscv_vmv_v_x_u32m8
#define VFMVFS_FLOAT_M1         __riscv_vfmv_f_s_f32m1_f32
#define VSLIDEDOWN_UINT         __riscv_vslidedown_vx_u32m8
#define VMVVXS_UINT             __riscv_vmv_x_s_u32m8_u32
#endif

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

    FLOAT_V_T vx, v_max;
    UINT_V_T v_max_index;
    MASK_T mask;
  
    size_t vlmax = VSETVL_MAX;
    v_max_index = VMVVX_UINT(0, vlmax);
    v_max = VFMVVF_FLOAT(-FLT_MAX, vlmax);
    BLASLONG j=0;
    FLOAT maxf=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 greater than v_max
            mask = VMFLTVV_FLOAT(v_max, vx, vl);
            v_max_index = VIDV_MASK_UINT_TU(mask, v_max_index, vl);
            v_max_index = VADDVX_MASK_UINT_TU(mask, v_max_index, v_max_index, j, vl);

            //update v_max and start_index j
            v_max = VFMAXVV_FLOAT_TU(v_max, v_max, 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 greater than v_max
            mask = VMFLTVV_FLOAT(v_max, vx, vl);
            v_max_index = VIDV_MASK_UINT_TU(mask, v_max_index, vl);
            v_max_index = VADDVX_MASK_UINT_TU(mask, v_max_index, v_max_index, j, vl);

            //update v_max and start_index j
            v_max = VFMAXVV_FLOAT_TU(v_max, v_max, vx, vl);
        }
  
    }

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

    v_res = VFREDMAXVS_FLOAT(v_max, v_res, vlmax);
    maxf = VFMVFS_FLOAT_M1(v_res);
    mask = VMFGEVF_FLOAT(v_max, maxf, vlmax);
    max_index = VFIRSTM(mask, vlmax);
    
    v_max_index = VSLIDEDOWN_UINT(v_max_index, max_index, vlmax);
    max_index = VMVVXS_UINT(v_max_index);

    return(max_index+1);
}