You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
67 lines
1.9 KiB
67 lines
1.9 KiB
/*
|
|
* @(#)Instruction.java 2.1 2003/10/07
|
|
*
|
|
* Copyright (C) 1999, 2003 D.A. Watt and D.F. Brown
|
|
* Dept. of Computing Science, University of Glasgow, Glasgow G12 8QQ Scotland
|
|
* and School of Computer and Math Sciences, The Robert Gordon University,
|
|
* St. Andrew Street, Aberdeen AB25 1HG, Scotland.
|
|
* All rights reserved.
|
|
*
|
|
* This software is provided free for educational use only. It may
|
|
* not be used for commercial purposes without the prior written permission
|
|
* of the authors.
|
|
*/
|
|
|
|
package triangle.abstractMachine;
|
|
|
|
import java.io.DataInputStream;
|
|
import java.io.DataOutputStream;
|
|
import java.io.EOFException;
|
|
import java.io.IOException;
|
|
|
|
public class Instruction {
|
|
|
|
// Java has no type synonyms, so the following representations are
|
|
// assumed:
|
|
//
|
|
// type
|
|
// OpCode = 0..15; {4 bits unsigned}
|
|
// Length = 0..255; {8 bits unsigned}
|
|
// Operand = -32767..+32767; {16 bits signed}
|
|
|
|
// Represents TAM instructions.
|
|
final OpCode opCode;
|
|
final Register register;
|
|
final int length;
|
|
int operand; // Not final to allow for patching jump address
|
|
|
|
public Instruction(OpCode opcode, Register register, int length, int operand) {
|
|
this.opCode = opcode;
|
|
this.register = register;
|
|
this.length = length;
|
|
this.operand = operand;
|
|
}
|
|
|
|
public void setOperand(int operand) {
|
|
this.operand = operand;
|
|
}
|
|
|
|
public void write(DataOutputStream output) throws IOException {
|
|
output.writeInt(opCode.ordinal());
|
|
output.writeInt(register.ordinal());
|
|
output.writeInt(length);
|
|
output.writeInt(operand);
|
|
}
|
|
|
|
public static Instruction read(DataInputStream input) throws IOException {
|
|
try {
|
|
var opCode = OpCode.values()[input.readInt()];
|
|
var register = Register.values()[input.readInt()];
|
|
var length = input.readInt();
|
|
var operand = input.readInt();
|
|
return new Instruction(opCode, register, length, operand);
|
|
} catch (EOFException s) {
|
|
return null;
|
|
}
|
|
}
|
|
}
|
|
|