Messages in this thread |  | | From | "Lyle Coder" <> | Subject | Re: Question: Using floating point in the kernel | Date | Wed, 20 Sep 2000 01:50:05 GMT |
| |
Hello, You cannot use MMX registers in the kernel either, since the kernel doesen't save and restore FX state (fxsave, fxrstor) either (just like (fsave/frstor).
Best Wishes, Lyle
** 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
When replying to a mailing-list message, please don't cc: me, because then I'll just get two copies of the same message. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/ _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
Share information about yourself, create your own public profile at http://profiles.msn.com.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
|  |