orc.b

Bitware OR-combine, byte granule

This instruction is defined by:

anyOf:
- B, version >= 0
- Zbb, version >= 0

This instruction is included in the following profiles:

RVA22S64 (Mandatory)
RVA22U64 (Mandatory)

Encoding

Assembly format

orc.b rd, rs1, rs2

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

M	HS	U	VS	VU
Always	Always	Always	Always	Always

Always

Decode Variables

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

Execution

IDL
Sail

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;

{
  let rs1_val = X(rs1);
  result : xlenbits = zeros();
  foreach (i from 0 to (sizeof(xlen) - 8) by 8)
    result[(i + 7) .. i] = if rs1_val[(i + 7) .. i] == zeros()
                           then 0x00
                           else 0xFF;
  X(rd) = result;
  RETIRE_SUCCESS
}

Exceptions

This instruction may result in the following synchronous exceptions:

IllegalInstruction