fix conditional jumps in the trampoline sometimes having wrong opcodes

geode-sdk · May 6, 2024 · a416a7b · a416a7b · altalk23 · May 6, 2024
1 parent ada6508
commit a416a7b
Showing 1 changed file with 7 additions and 1 deletion.
diff --git a/src/generator/X86Generator.cpp b/src/generator/X86Generator.cpp
@@ -257,9 +257,15 @@ Result<> X86HandlerGenerator::relocateInstruction(cs_insn* insn, uint8_t* buffer
 			trampolineAddress += 5;
 		}
 		else {
+			uint8_t opCode;
+			switch (id) {
+				case X86_INS_JE:  opCode = 0x74; break;
+				case X86_INS_JNE: opCode = 0x75; break;
+				default:          opCode = 0x0f; break;
+			}
 			// conditional jumps
 			// res = dst - src - 6
-			std::array<uint8_t, 6> jmp = {0x0f, 0, 0, 0, 0, 0};
+			std::array<uint8_t, 6> jmp = {opCode, 0, 0, 0, 0, 0};
 			int addrBytes = jmpTargetAddr - trampolineAddress - 6;
 			if (detail->x86.operands[0].size == 1) {
 				jmp[1] = insn->bytes[0] + 0x10;