vabd.vv
Vector Single-Width Signed Integer Absolute Difference
This instruction is defined by:
Synopsis
Computes the element-wise absolute difference of two signed integer SEW-bit source operands vs1 and vs2 and writes the result to vd according to mask vm.
Reserved when SEW is neither 8 nor 16.
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
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Pruned, XLEN == 64
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Original
VectorState state = vector_state();
if (state.sew != 8 && state.sew != 16) {
raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
VectorLmulType lmul_type = state.lmul_type;
XReg vlen = 17'128;
XReg vlmax;
if (lmul_type == VectorLmulType::Multiply) {
vlmax = (64'128 << state.log2_lmul) >> state.log2_sew;
} else {
vlmax = (64'128 >> state.log2_lmul) >> state.log2_sew;
}
for (U32 i = CSR[vstart].VALUE; i < CSR[vl].VALUE; i) {
U32 start_bit_pos = i * state.sew;
U32 end_bit_pos = start_bit_pos pass:[+] state.sew - 1;
if pass:[(]vm == 1'b1 || V[0][i:i] == 1'b1) {
if pass:[(]$signed(V[vs2][end_bit_pos:start_bit_pos]) >= $signed(++V[vs1][end_bit_pos:start_bit_pos])) {
V[vd][end_bit_pos:start_bit_pos] = V[vs2][end_bit_pos:start_bit_pos] - V[vs1][end_bit_pos:start_bit_pos];
} else {
V[vd][end_bit_pos:start_bit_pos] = V[vs1][end_bit_pos:start_bit_pos] - V[vs2][end_bit_pos:start_bit_pos];
}
}
}
CSR[vstart].VALUE = 0;VectorState state = vector_state();
if (state.sew != 8 && state.sew != 16) {
raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
VectorLmulType lmul_type = state.lmul_type;
XReg vlen = VLEN;
XReg vlmax;
if (lmul_type == VectorLmulType::Multiply) {
vlmax = (vlen << state.log2_lmul) >> state.log2_sew;
} else {
vlmax = (vlen >> state.log2_lmul) >> state.log2_sew;
}
for (U32 i = CSR[vstart].VALUE; i < CSR[vl].VALUE; i) {
U32 start_bit_pos = i * state.sew;
U32 end_bit_pos = start_bit_pos pass:[+] state.sew - 1;
if pass:[(]vm == 1'b1 || V[0][i:i] == 1'b1) {
if pass:[(]$signed(V[vs2][end_bit_pos:start_bit_pos]) >= $signed(++V[vs1][end_bit_pos:start_bit_pos])) {
V[vd][end_bit_pos:start_bit_pos] = V[vs2][end_bit_pos:start_bit_pos] - V[vs1][end_bit_pos:start_bit_pos];
} else {
V[vd][end_bit_pos:start_bit_pos] = V[vs1][end_bit_pos:start_bit_pos] - V[vs2][end_bit_pos:start_bit_pos];
}
}
}
CSR[vstart].VALUE = 0;