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Re: [MIPS] Use conditional traps for BUG_ON on MIPS II and better.

To: ralf@linux-mips.org
Subject: Re: [MIPS] Use conditional traps for BUG_ON on MIPS II and better.
From: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Date: Sat, 16 Dec 2006 01:26:45 +0900 (JST)
Cc: linux-mips@linux-mips.org, qemu-devel@nongnu.org
In-reply-to: <20061203213518.GA22225@linux-mips.org>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <S20037651AbWK3BXW/20061130012322Z+10503@ftp.linux-mips.org> <20061204.015327.36921579.anemo@mba.ocn.ne.jp> <20061203213518.GA22225@linux-mips.org>
Sender: linux-mips-bounce@linux-mips.org
On Sun, 3 Dec 2006 21:35:18 +0000, Ralf Baechle <ralf@linux-mips.org> wrote:
> > It seems this commit break QEMU kernel ...  or QEMU can not interpret
> > the TNE instruction correctly?
> 
> Thiemo says that's indeed a possibility.  Probably that feature has not
> been well tested in qemu.

I found the bug.  "Trap If XXX" instructions are translated as it was
"Trap If XXX Immediate".

Index: target-mips/translate.c
===================================================================
RCS file: /sources/qemu/qemu/target-mips/translate.c,v
retrieving revision 1.27
diff -u -r1.27 translate.c
--- target-mips/translate.c     10 Dec 2006 22:08:10 -0000      1.27
+++ target-mips/translate.c     15 Dec 2006 16:16:07 -0000
@@ -1276,6 +1276,7 @@
             GEN_LOAD_REG_TN(T1, rt);
             cond = 1;
         }
+        break;
     case OPC_TEQI:
     case OPC_TGEI:
     case OPC_TGEIU:

---
Atsushi Nemoto

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