_ Git - BearSSL/blob - T0/OpcodeJump.cs

   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 }