vfirst.m

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

vfirst.m vm, vs2, rd

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> rd = $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
}