Subject: Re: Prentium MMX for NetBSD-current
To: Martin Husemann <>
From: Jason Thorpe <>
List: current-users
Date: 01/27/1997 18:21:55
[ Man, I have a lot of mail to catch up on... ]

On Sat, 25 Jan 1997 10:40:35 +0100 
 Martin Husemann <> wrote:

 > I made a small patch to locore to detect a MMX CPU and display the =
 > result.
 > This was not needed, it runs just out of the box.

...this is now also in the -current kernel, BTW.

 > I haven't punted the system heavily, but it seems to work for me. Of =
 > course it
 > doesn't use any of the MMX extensions.

Right... the reason for this is because using MMX would require
NPX/MMX state to be saved for the kernel as well as userland.  This
is also the reason why we don't allow the kernel to do floating point
operations, except to manipulate the FPU on behalf of the user.

As I understand it, MMX is really for user applications, and is
probably not appropriate for use in the kernel.

Jason R. Thorpe                             
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