On Wed, Apr 16, 2003 at 01:07:41AM +0200, Martin Husemann wrote:
> There are different restrictions on register usage, for the assembler
> versions.

Maybe just a special case of the above, but:

and the FPU state frobing, which you neither want to do nor can do at all
in the userland version. (If your arch needs the FPU enabled for some of
the instructions used in the kernel version)

Martin