vredsum.vs

No synopsis available.

This instruction is defined by:

V, version >= 0

This instruction is included in the following profiles:

RVA22U64 (Optional)

Encoding

Assembly format

vredsum.vs vm, vs2, vs1, vd

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> vs1 = $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_vs = get_num_elem(LMUL_pow, SEW);
  let num_elem_vd = get_num_elem(0, SEW); /* vd regardless of LMUL setting */

  if illegal_reduction() then { handle_illegal(); return RETIRE_FAIL };

  if unsigned(vl) == 0 then return RETIRE_SUCCESS; /* if vl=0, no operation is performed */

  let 'n = num_elem_vs;
  let 'd = num_elem_vd;
  let 'm = SEW;

  let vm_val  : vector('n, dec, bool)     = read_vmask(num_elem_vs, vm, 0b00000);
  let vd_val  : vector('d, dec, bits('m)) = read_vreg(num_elem_vd, SEW, 0, vd);
  let vs2_val : vector('n, dec, bits('m)) = read_vreg(num_elem_vs, SEW, LMUL_pow, vs2);
  let mask    : vector('n, dec, bool)     = init_masked_source(num_elem_vs, LMUL_pow, vm_val);

  sum : bits('m) = read_single_element(SEW, 0, vs1); /* vs1 regardless of LMUL setting */
  foreach (i from 0 to (num_elem_vs - 1)) {
    if mask[i] then {
      sum = match funct6 {
        MVV_VREDSUM   => sum + vs2_val[i],
        MVV_VREDAND   => sum & vs2_val[i],
        MVV_VREDOR    => sum | vs2_val[i],
        MVV_VREDXOR   => sum ^ vs2_val[i],
        MVV_VREDMIN   => to_bits(SEW, min(signed(vs2_val[i]), signed(sum))),
        MVV_VREDMINU  => to_bits(SEW, min(unsigned(vs2_val[i]), unsigned(sum))),
        MVV_VREDMAX   => to_bits(SEW, max(signed(vs2_val[i]), signed(sum))),
        MVV_VREDMAXU  => to_bits(SEW, max(unsigned(vs2_val[i]), unsigned(sum)))
      }
    }
  };

  write_single_element(SEW, 0, vd, sum);
  /* other elements in vd are treated as tail elements, currently remain unchanged */
  /* TODO: configuration support for agnostic behavior */
  vstart = zeros();
  RETIRE_SUCCESS
}