From 214798c3c1e4095f08b0134d0437830635251ada Mon Sep 17 00:00:00 2001
From: zeromus <zeromus@users.sf.net>
Date: Fri, 26 Dec 2008 20:05:43 +0000
Subject: [PATCH] fix an issue which could cause an invalid SWI in thumb mode
 to crash the emulator

---
 desmume/src/thumb_instructions.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/desmume/src/thumb_instructions.cpp b/desmume/src/thumb_instructions.cpp
index 1158d107f..8a275d0af 100644
--- a/desmume/src/thumb_instructions.cpp
+++ b/desmume/src/thumb_instructions.cpp
@@ -902,7 +902,10 @@ TEMPLATE static  u32 FASTCALL OP_SWI_THUMB()
      }
      else
      {
-        u32 swinum = cpu->instruction & 0xFF;
+		 //zero 25-dec-2008 - in arm, we were masking to 0x1F. 
+		 //this is probably safer since an invalid opcode could crash the emu
+		 //u32 swinum = cpu->instruction & 0xFF;
+		 u32 swinum = cpu->instruction & 0x1F;
         return cpu->swi_tab[swinum](cpu) + 3;  
      }
      //return 3;