private static byte or(byte rmv, byte lmv) {
		// See truth table for OR above
		if (lmv == 3 || rmv == 3) {
			return 3;
		}
		else if (lmv == 2 && rmv == 2) {
			return 2;
		}
		return 0;
	}
Compute the arithmetic difference: this masked long minus another

@param that the other masked long.
@return the result.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/app/plugin/assembler/sleigh/expr/MaskedLong.java