Re: Question: Using floating point in the kernel

From: Timur Tabi (ttabi@interactivesi.com)
Date: Tue Sep 19 2000 - 12:36:36 EST

** Reply to message from "Richard B. Johnson" <root@chaos.analogic.com> on Tue,
19 Sep 2000 11:58:34 -0400 (EDT)

> Tell the driver maintainer that you found a BUG. There is no floating-
> point allowed in the kernel because the state of the FP Unit is
> undefined in the kernel. If you 'define' it, i.e., `finit` then you
> will mess up somebody who was using the FP Unit in user-mode.
>
> Also, the '386 FP emulation, which is still supported, can produce a
> double-fault if you try to use it (at some places) in kernel-mode
> code.
>
> Basically, there is nothing in the kernel that will ever require
> floating point. Use fixed point if you need 'decimals' and stuff for
> printing.

What about MMX? It uses floating point registers, but it's not technically
floating point. 

-- 
Timur Tabi - ttabi@interactivesi.com
Interactive Silicon - http://www.interactivesi.com

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