vfirst.m

No synopsis available

No description available.

Assembly format

vfirst.m rd, vs2, vm

Decode Variables

Bits<1> vm = $encoding[25];
Bits<5> vs2 = $encoding[24:20];
Bits<5> xd = $encoding[11:7];

Execution

  • IDL

  • Sail

{
  let SEW      = get_sew();
  let LMUL_pow = get_lmul_pow();
  let num_elem = unsigned(vlenb) * 8;

  if illegal_vd_unmasked() | not(assert_vstart(0)) then { handle_illegal(); return RETIRE_FAIL };

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

  let vm_val  : vector('n, dec, bool) = read_vmask(num_elem, vm, 0b00000);
  let vs2_val : vector('n, dec, bool) = read_vmask(num_elem, 0b0, vs2);
  result      : vector('n, dec, bool) = undefined;
  mask        : vector('n, dec, bool) = undefined;

  (result, mask) = init_masked_result_cmp(num_elem, SEW, 0, vs2_val, vm_val);

  index : int = -1;
  foreach (i from 0 to (num_elem - 1)) {
    if index == -1 then {
      if mask[i] & vs2_val[i] then index = i;
    };
  };

  X(rd) = to_bits(sizeof(xlen), index);
  vstart = zeros();
  RETIRE_SUCCESS
}

Encoding

svg

Defining extension

  • V, version >= V@1.0.0

Access

M HS U VS VU

Always

Always

Always

Always

Always

Containing profiles

  • Mandatory: RVA23M64, RVA23S64, RVA23U64

  • Optional: RVA22S64, RVA22U64, RVB23M64, RVB23S64, RVB23U64