mirrors/ParkanPlayground
0
Fork 0
mirror of https://github.com/sampletext32/ParkanPlayground.git synced 2025-06-20 00:18:02 +03:00
Code Issues Releases Activity

Fixed ConditionalJumpHandler to correctly implement x86 architecture specifications

Browse Source
This commit is contained in:
bird_egop
2025-04-12 21:09:41 +03:00
parent bd251b6c06
commit bf5fcdd2ff
2 changed files with 212 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
X86Disassembler/X86/Handlers/ConditionalJumpHandler.cs
View File

@ -1,5 +1,7 @@
namespace X86Disassembler.X86.Handlers;
using System;
/// <summary>
/// Handler for conditional jump instructions (0x70-0x7F)
/// </summary>
@ -46,6 +48,7 @@ public class ConditionalJumpHandler : InstructionHandler
int index = opcode - 0x70;
instruction.Mnemonic = ConditionalJumpMnemonics[index];
// Get the current position in the code buffer
int position = Decoder.GetPosition();
if (position >= Length)
@ -55,19 +58,21 @@ public class ConditionalJumpHandler : InstructionHandler
// Read the relative offset
sbyte offset = (sbyte)CodeBuffer[position];
// According to x86 architecture, the jump offset is relative to the instruction following the jump
// For a conditional jump, the instruction is 2 bytes: opcode (1 byte) + offset (1 byte)
// Calculate the target address:
// 1. Start with the current position (where the offset byte is)
// 2. Add 1 to account for the size of the offset byte itself
// 3. Add the offset value
int targetAddress = position + 1 + offset;
// Move the decoder position past the offset byte
Decoder.SetPosition(position + 1);
// In x86 architecture, the jump offset is relative to the next instruction
// However, for our disassembler output, we're just showing the raw offset value
// as per the test requirements
// Note: In a real x86 disassembler, we would calculate the actual target address:
// uint targetAddress = (uint)(position + offset + 1);
// This would be the absolute address in memory where execution would jump to
// But our tests expect just the raw offset value
// Set the operands to the raw offset value as expected by the tests
instruction.Operands = $"0x{(uint)offset:X8}";
// Set the operands to the calculated target address
instruction.Operands = $"0x{targetAddress:X8}";
return true;
}