vfclass.v

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

vfclass.v vm, vs2, 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> vd = $encoding[11:7];

Execution

IDL
Sail

{
  let rm_3b    = fcsr.FRM();
  let SEW      = get_sew();
  let LMUL_pow = get_lmul_pow();
  let num_elem = get_num_elem(LMUL_pow, SEW);

  if illegal_fp_normal(vd, vm, SEW, rm_3b) then { handle_illegal(); return RETIRE_FAIL };
  assert(SEW != 8);

  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, 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, vm_val);

  foreach (i from 0 to (num_elem - 1)) {
    if mask[i] then {
      result[i] = match vfunary1 {
        FVV_VSQRT      => {
                            let (fflags, elem) : (bits_fflags, bits('m)) = match 'm {
                              16  => riscv_f16Sqrt(rm_3b, vs2_val[i]),
                              32  => riscv_f32Sqrt(rm_3b, vs2_val[i]),
                              64  => riscv_f64Sqrt(rm_3b, vs2_val[i])
                            };
                            accrue_fflags(fflags);
                            elem
                          },
        FVV_VRSQRT7    => {
                            let (fflags, elem) : (bits_fflags, bits('m)) = match 'm {
                              16  => riscv_f16Rsqrte7(rm_3b, vs2_val[i]),
                              32  => riscv_f32Rsqrte7(rm_3b, vs2_val[i]),
                              64  => riscv_f64Rsqrte7(rm_3b, vs2_val[i])
                            };
                            accrue_fflags(fflags);
                            elem
                          },
        FVV_VREC7      => {
                            let (fflags, elem) : (bits_fflags, bits('m)) = match 'm {
                              16  => riscv_f16Recip7(rm_3b, vs2_val[i]),
                              32  => riscv_f32Recip7(rm_3b, vs2_val[i]),
                              64  => riscv_f64Recip7(rm_3b, vs2_val[i])
                            };
                            accrue_fflags(fflags);
                            elem
                          },
        FVV_VCLASS     => fp_class(vs2_val[i])
      }
    }
  };

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