Subject: Re: port-i386/8505: Some cyrix CPUs can be locked solid from userland
To: Dave Sainty <>
From: Matthew Orgass <>
List: netbsd-bugs
Date: 09/28/1999 22:20:12
On Wed, 29 Sep 1999, Dave Sainty wrote:

> I believe the lockup is restricted to pentium class CPUs.  

  Yes and no.  This is the "coma bug" which affects several types of Cyrix
CPUs. However, the fix is enabled for most affected Cyrix CPUs, just not
for 6x86MX machines.  See PR i386/7538 for the patch to enable the fix. 

  Note that there is also another bug in some Cyrix 6x86 CPUs that freezes
with the following code:

int main()
   asm ("foo:");
   asm ("cwtl");
   asm ("orl $0xe6ebe020,%eax");
   asm ("jle foo");
   asm ("addb %al,(%eax)");

   return 0;

  No known fix is available.

Matthew Orgass