xref: /freebsd/contrib/bearssl/T0/OpcodeJump.cs (revision f81cdf24ba5436367377f7c8e8f51f6df2a75ca7)
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 }
65