1  /*
 2   * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
 3   *
 4   * Permission is hereby granted, free of charge, to any person obtaining 
 5   * a copy of this software and associated documentation files (the
 6   * "Software"), to deal in the Software without restriction, including
 7   * without limitation the rights to use, copy, modify, merge, publish,
 8   * distribute, sublicense, and/or sell copies of the Software, and to
 9   * permit persons to whom the Software is furnished to do so, subject to
10   * the following conditions:
11   *
12   * The above copyright notice and this permission notice shall be 
13   * included in all copies or substantial portions of the Software.
14   *
15   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
16   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
18   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19   * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20   * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22   * SOFTWARE.
23   */
24  
25  using System;
26  using System.Collections.Generic;
27  
28  abstract class OpcodeJump : Opcode {
29  
30  	int disp;
31  
32  	internal OpcodeJump() : this(Int32.MinValue)
33  	{
34  	}
35  
36  	internal OpcodeJump(int disp)
37  	{
38  		this.disp = disp;
39  	}
40  
41  	internal override int JumpDisp {
42  		get {
43  			return disp;
44  		}
45  	}
46  
47  	internal override void Run(CPU cpu)
48  	{
49  		cpu.ipOff += disp;
50  	}
51  
52  	internal override void ResolveJump(int disp)
53  	{
54  		if (this.disp != Int32.MinValue) {
55  			throw new Exception("Jump already resolved");
56  		}
57  		this.disp = disp;
58  	}
59  
60  	internal override void FixUp(CodeElement[] gcode, int off)
61  	{
62  		gcode[off].SetJumpTarget(gcode[off + 1 + disp]);
63  	}
64  }