Subject: Re: lazy FPU context switching ports
To: Jason Thorpe <thorpej@shagadelic.org>
From: Matt Thomas <matt@3am-software.com>
List: tech-kern
Date: 07/11/2005 22:07:39
Jason Thorpe wrote:
> 
> On Jul 11, 2005, at 8:04 PM, Rui Paulo wrote:
> 
>> If no one is against this, please send me an email saying the ports  you
>> know that use/don't use lazy fpu context switching.
> 
> 
> I'm pretty sure that every platform that can support it does.  I  think
> this is basically "every FPU-supporting platform except for  m68k
> platforms".  m68k is the exception because I don't think there  is a way
> to disable the FPU (a requirement for lazy FP switching).

VAX always has the FPU enabled so it doesn't FP switch.  Heck VAX doesn't
have a separate FP register set.

> I don't see much value in creating such a table.

Does x86 lazily swap MMX/SSE* support as well?  PowerPC does lazily swap
AltiVec as well.
-- 
Matt Thomas                     email: matt@3am-software.com
3am Software Foundry              www: http://3am-software.com/bio/matt/
Cupertino, CA              disclaimer: I avow all knowledge of this message.