public String toMachineString() {
		String machineString;
		if (OPCODE.getValue() == 13 || OPCODE.getValue() == 10) { //For HALT and SKZ instructions with no fields
			return OPCODE.toString();
		}
		
		if (OPCODE.getValue() > 7 && OPCODE.getValue() < 10) { //For branch instructions with only one field
			machineString = OPCODE.getValue() + " " + Integer.toHexString(this.getField1()).toUpperCase();
			return machineString;
		}
		
		//For all those instructions with two fields (Transfer and Arithmetic).
		machineString = OPCODE.getValue() + " " + Integer.toHexString(this.getField1()).toUpperCase() + " " + 
				Integer.toHexString(this.getField2()).toUpperCase();
		return machineString;
	}