orc.b

Bitware OR-combine, byte granule

This instruction is defined by:

Encoding

Synopsis

Combines the bits within each byte using bitwise logical OR. This sets the bits of each byte in the result rd to all zeros if no bit within the respective byte of rs is set, or to all ones if any bit within the respective byte of rs is set.

Access

Always

Decode Variables

Bits<5> rs1 = $encoding[19:15];
Bits<5> rd = $encoding[11:7];

Execution

Pruned, XLEN == 64
Original

XReg input = X[rs1];
XReg output = 0;
for (U32 i = 0; i < (56); i = i + 8) {
  output[(i + 7):i] = (input[(i + 7):i] == 0) ? 8'd0 : ~8'd0;
}
X[rd] = output;

if (implemented?(ExtensionName::B) && (CSR[misa].B == 1'b0)) {
  raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
XReg input = X[rs1];
XReg output = 0;
for (U32 i = 0; i < (xlen() - 8); i = i + 8) {
  output[(i + 7):i] = (input[(i + 7):i] == 0) ? 8'd0 : ~8'd0;
}
X[rd] = output;