vabs.v

Vector Single-Width Signed Integer Absolute

This instruction is defined by:

Encoding

Synopsis

An absolute value operation is performed on each element of vs2, storing the result in vector register vd according to mask vm.

vabs.v supports SEW of 8, 16, and 32 when Zve32x is implemented. When Zve64x is implemented, vabs.v also supports SEW of 64.

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

Pruned, XLEN == 64
Original

VectorState state = vector_state();
VectorLmulType lmul_type = state.lmul_type;
XReg vlen = 17'128;
XReg vlmax;
if (lmul_type == VectorLmulType::Multiply) {
  vlmax = (64'128 << state.log2_lmul) >> state.log2_sew;
} else {
  vlmax = (64'128 >> state.log2_lmul) >> state.log2_sew;
}
for (U32 i = CSR[vstart].VALUE; i < CSR[vl].VALUE; i) {
  U32 start_bit_pos = i * state.sew;
  U32 end_bit_pos = start_bit_pos pass:[+] state.sew - 1;
  if pass:[(]vm == 1'b1 || V[0][i:i] == 1'b1) {
    if pass:[(]V[vs2][end_bit_pos:end_bit_pos] == 1'b1) {
      V[vd][end_bit_pos:start_bit_pos] = -$signed(++V[vs2][end_bit_pos:start_bit_pos]);
    } else {
      V[vd][end_bit_pos:start_bit_pos] = V[vs2][end_bit_pos:start_bit_pos];
    }
  }
}
CSR[vstart].VALUE = 0;

VectorState state = vector_state();
VectorLmulType lmul_type = state.lmul_type;
XReg vlen = VLEN;
XReg vlmax;
if (lmul_type == VectorLmulType::Multiply) {
  vlmax = (vlen << state.log2_lmul) >> state.log2_sew;
} else {
  vlmax = (vlen >> state.log2_lmul) >> state.log2_sew;
}
for (U32 i = CSR[vstart].VALUE; i < CSR[vl].VALUE; i) {
  U32 start_bit_pos = i * state.sew;
  U32 end_bit_pos = start_bit_pos pass:[+] state.sew - 1;
  if pass:[(]vm == 1'b1 || V[0][i:i] == 1'b1) {
    if pass:[(]V[vs2][end_bit_pos:end_bit_pos] == 1'b1) {
      V[vd][end_bit_pos:start_bit_pos] = -$signed(++V[vs2][end_bit_pos:start_bit_pos]);
    } else {
      V[vd][end_bit_pos:start_bit_pos] = V[vs2][end_bit_pos:start_bit_pos];
    }
  }
}
CSR[vstart].VALUE = 0;