From ef5de6091b903bac7a0d4f34673a69efbea27906 Mon Sep 17 00:00:00 2001
From: Jaklyy <102590697+Jaklyy@users.noreply.github.com>
Date: Thu, 7 Nov 2024 13:16:39 -0500
Subject: [PATCH] t blx long with bit 0 set should raise an exception

fixes a bug with gbarunner3
---
 src/ARMInterpreter_Branch.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/ARMInterpreter_Branch.cpp b/src/ARMInterpreter_Branch.cpp
index 623be41a..88b14ab7 100644
--- a/src/ARMInterpreter_Branch.cpp
+++ b/src/ARMInterpreter_Branch.cpp
@@ -104,6 +104,9 @@ void T_BL_LONG_1(ARM* cpu)
 
 void T_BL_LONG_2(ARM* cpu)
 {
+    if ((cpu->CurInstr & 0x1801) == 0x0801) // "BLX" with bit 0 set is an unvalid instruction.
+        return T_UNK(cpu); // TODO: Check ARM7 for exceptions
+    
     s32 offset = (cpu->CurInstr & 0x7FF) << 1;
     u32 pc = cpu->R[14] + offset;
     cpu->R[14] = (cpu->R[15] - 2) | 1;