Re: Question: Using floating point in the kernel

[John Alvord]

On Wed, 20 Sep 2000 22:37:29 -0700, "Lyle Coder" <[EMAIL PROTECTED]>
wrote:

>Hi
>The real issue is that if you use MMX or FP state, the kernel _must_ save
>and restore the original state other wise user programs will see corruption.
>We all know this too well since redhat's 6.1 (I think) kernel had this
>optimized MMX functions that _screwed_ up user programs.  The fact is... it
>is tricky to save and restore state (device not available and all).
>The basic kernel itself does not provide support for kernel code to use
>these registers.  If some device drivers or some modifications to the kernel
>are using it.. then I hope they have the save/restore path right

A 2.5-time problem is that portions of the kernel are planned to
become interruptible... so saving and restoring around a certain usage
would be insufficient.

john
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