Method decodeRegister

src/chap13/Opcode.java:32–32

(byte operand)

            return (byte)-(reg + 1);
    } 
    public static int decodeRegister(byte operand) { return -1 - operand; }
    public static byte encodeOffset(int offset) {
        if (offset > Byte.MAX_VALUE)
            throw new StoneException("too big byte offset");