romcc and EPIA

[Eric W. Biederman]

Stefan Reinauer <stepan at suse.de> writes:

> * SONE Takeshi <ts1 at tsn.or.jp> [031003 10:47]:
> > I noticed romcc has support for MMX/SSE registers and epia/Config.lb
> > does not use it. Is there any problem using MMX registers on a C3?
> > I also wonder why -mcpu=p3 is required to enable MMX support of romcc.
> > IIRC, MMX has been supported since Pentium MMX and up, and Pentium III
> > adds SSE.

The current set of options to romcc are mostly something I hacked together
one day.

-mmmx or -msse sound like a better mapping.  The only advantage to doing
by cpu is it is easier to remember which cpu you have, but there are
other ways to achieve that effect.

Patches welcome if someone wants to change the options.

> On CPUs prior to PIII the mmx registers were shared with the floating
> point unit. Switching between those was extremely slow. Don't know
> whether this is an issue, since LinuxBIOS does not use fp 

mmx registers are architecturally if not practically shared with
the floating point registers.

Eric