vsbc.vxm

No synopsis available.

This instruction is defined by:

V, version >= 0

This instruction is included in the following profiles:

RVA22U64 (Optional)

Encoding

Assembly format

vsbc.vxm vs2, rs1, vd

Synopsis

No description available.

Access

M	HS	U	VS	VU
Always	Always	Always	Always	Always

Always

Decode Variables

Bits<5> vs2 = $encoding[24:20];
Bits<5> rs1 = $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);

  if illegal_vd_masked(vd) then { handle_illegal(); return RETIRE_FAIL };

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

  /* for bypassing normal masking in init_masked_result */
  vec_trues : vector('n, dec, bool) = undefined;
  foreach (i from 0 to (num_elem - 1)) {
    vec_trues[i] = true
  };

  let vm_val  : vector('n, dec, bool)     = read_vmask_carry(num_elem, 0b0, 0b00000);
  let rs1_val : bits('m)                  = get_scalar(rs1, SEW);
  let vs2_val : vector('n, dec, bits('m)) = read_vreg(num_elem, SEW, LMUL_pow, vs2);
  let vd_val  : vector('n, dec, bits('m)) = read_vreg(num_elem, SEW, LMUL_pow, vd);
  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, vec_trues);

  foreach (i from 0 to (num_elem - 1)) {
    if mask[i] then {
      result[i] = match funct6 {
        VXMS_VADC     => to_bits(SEW, unsigned(vs2_val[i]) + unsigned(rs1_val) + unsigned(bool_to_bits(vm_val[i]))),
        VXMS_VSBC     => to_bits(SEW, unsigned(vs2_val[i]) - unsigned(rs1_val) - unsigned(bool_to_bits(vm_val[i])))
      }
    }
  };

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