[mythtv] [PATCH] march documentation update

[Ivor Hewitt]

On Tuesday 28 Dec 2004 02:40, Daniel Thor Kristjansson wrote:
> On Mon, 27 Dec 2004, Mark Spieth wrote:
> ]yes I see. sorry forgot to look.
> ]however you used __MMX__ which doesnt seem to be defined on my system. at
> ]least explicitly.
> ]however MMX is. am I missing something?
> ]still trying to find a good fix for the live end of file thing.
> ]cheers
> ]mark
>
> This patch to the HOWTO-5 document tells people how to compile for a
> specific processor, such as one that supports MMX.
>
> Someday we should change the compiling setup so that these things are
> set up automagically when not cross-compiling. Perhaps using configure?
> Until then, this will help people compile for the right architecture,
> at least if it is an x86 derivative.
>
> -- Daniel

Daniel, 

The VIA C3 processor supports 3Dnow/SSE and MMX instructions, so compiling 
with i586 is probably unnecessarily restrictive.

So for the C3: -march=i586 -m3dnow -mmmx
and Nehemia: -march=i686 -msse -mmmx -mfpmath=sse

Also recent gcc versions (>3.3?) support "-march=c3" (MMX+3DN) or 
"-march=c3-2" (MMX+SSE) anyway which is even simpler.

Cheers,

-- 
Ivor Hewitt.
http://www.ivor.it - tech | http://www.ivor.org - hedge