vnsra.wi

No synopsis available.

This instruction is defined by:

V, version >= 0

This instruction is included in the following profiles:

RVA22S64 (Optional)
RVA22U64 (Optional)

Encoding

Assembly format

vnsra.wi vm, vs2, vd, imm

Synopsis

No description available.

Access

M	HS	U	VS	VU
Always	Always	Always	Always	Always

Always

Decode Variables

Bits<1> vm = $encoding[25];
Bits<5> vs2 = $encoding[24:20];
Bits<5> simm5 = $encoding[19:15];
Bits<5> vd = $encoding[11:7];

Execution

IDL
Sail

{
  let SEW      = get_sew();
  let LMUL_pow = get_lmul_pow();
  let num_elem = get_num_elem(LMUL_pow, SEW);
  let SEW_widen      = SEW * 2;
  let LMUL_pow_widen = LMUL_pow + 1;

  if  illegal_variable_width(vd, vm, SEW_widen, LMUL_pow_widen) |
      not(valid_reg_overlap(vs2, vd, LMUL_pow_widen, LMUL_pow))
  then { handle_illegal(); return RETIRE_FAIL };

  let 'n = num_elem;
  let 'm = SEW;
  let 'o = SEW_widen;

  let vm_val  : vector('n, dec, bool)     = read_vmask(num_elem, vm, 0b00000);
  let vd_val  : vector('n, dec, bits('m)) = read_vreg(num_elem, SEW, LMUL_pow, vd);
  let imm_val : bits('m)                  = sign_extend(simm);
  let vs2_val : vector('n, dec, bits('o)) = read_vreg(num_elem, SEW_widen, LMUL_pow_widen, vs2);
  result      : vector('n, dec, bits('m)) = undefined;
  mask        : vector('n, dec, bool)     = undefined;

  (result, mask) = init_masked_result(num_elem, SEW, LMUL_pow, vd_val, vm_val);

  assert(SEW_widen <= 64);
  foreach (i from 0 to (num_elem - 1)) {
    if mask[i] then {
      result[i] = match funct6 {
        NIS_VNSRL  => {
                        let shift_amount = get_shift_amount(imm_val, SEW_widen);
                        slice(vs2_val[i] >> shift_amount, 0, SEW)
                      },
        NIS_VNSRA  => {
                        let shift_amount = get_shift_amount(imm_val, SEW_widen);
                        let v_double : bits('o * 2) = sign_extend(vs2_val[i]);
                        let arith_shifted : bits('o) = slice(v_double >> shift_amount, 0, SEW_widen);
                        slice(arith_shifted, 0, SEW)
                      }
      }
    }
  };

  write_vreg(num_elem, SEW, LMUL_pow, vd, result);
  vstart = zeros();
  RETIRE_SUCCESS
}