[mythtv] [PATCH] march documentation update

[Daniel Thor Kristjansson]

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
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Index: docs/mythtv-HOWTO-5.html
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RCS file: /var/lib/mythcvs/mythtv/docs/mythtv-HOWTO-5.html,v
retrieving revision 1.74
diff -u -r1.74 mythtv-HOWTO-5.html
--- docs/mythtv-HOWTO-5.html	21 Dec 2004 04:10:35 -0000	1.74
+++ docs/mythtv-HOWTO-5.html	28 Dec 2004 02:33:06 -0000
@@ -82,35 +82,36 @@
 <A HREF="http://lame.sourceforge.net/">http://lame.sourceforge.net/</A>.  Download the source code to v3.93.1
 by following the links from "About".</P>
 
-<H2><A NAME="nonintelcpu_"></A> <A NAME="ss5.1">5.1</A> <A HREF="mythtv-HOWTO.html#toc5.1">Notes on compiling on a system with non-Intel processors </A>
+<H2><A NAME="cpuspecificoptimizations_"></A> <A NAME="ss5.1">5.1</A> <A HREF="mythtv-HOWTO.html#toc5.1">Notes on compiling for different processors</A>
 </H2>
 
 <P>If you've got a system with an AMD K6-2 or a VIA C3 processor, make the
 following change in the <CODE>settings.pro</CODE> file.</P>
-<P>Look for 
-<PRE>
--march=pentiumpro
-</PRE>
- 
-and replace it with
-<PRE>
--march=i586
-</PRE>
- 
-before you compile.</P>
-<P>Recent AMD processors, like the Duron, Thunderbird and Athlon don't need this
-change.</P>
-<P>If you have an AMD64, look for 
-<PRE>
--march=pentiumpro
-</PRE>
- 
-and replace it with
-<PRE>
--march=opteron
-</PRE>
- 
-before you compile.</P>
+<P>Look for <TT>-march=pentiumpro</TT> and replace it with <TT>-march=i586</TT> before you compile.
+Recent AMD processors, like the Duron, Thunderbird and Athlon don't need this change.</P>
+
+<P>If you have an AMD64, you may wish to look for <TT>-march=pentiumpro</TT> and replace it with
+<TT>-march=opteron</TT> before you compile, to take advantage of the processor's capabilities.</P>
+
+<P>Finally, if you have an Intel processor other than the Pentium Pro you may with to specify it as well, replace
+<TT>-march=pentiumpro</TT> and replace it with one of
+<DL>
+<DT><TT>-march=i586             </TT></DT><DD>for the Intel Pentium CPU without MMX</DD>
+<DT><TT>-march=pentium-mmx      </TT></DT><DD>for the Intel PentiumMMX CPU based on Pentium core with MMX</DD>
+<DT><TT>-march=pentium2         </TT></DT><DD>for the Intel Pentium2 CPU based on PentiumPro core with MMX</DD>
+<DT><TT>-march=pentium3         </TT></DT><DD>for the Intel Pentium3 CPU based on PentiumPro core with MMX and SSE</DD>
+<DT><TT>-march=pentium-m        </TT></DT><DD>for the Low power version of Intel Pentium3 CPU with MMX, SSE and SSE2</DD>
+<DT><TT>-march=pentium4         </TT></DT><DD>for the Intel Pentium4 CPU with MMX, SSE and SSE2</DD>
+<DT><TT>-march=prescott         </TT></DT><DD>for the Intel Pentium4 CPU with MMX, SSE, SSE2 and SSE3</DD>
+<DT><TT>-march=nocona           </TT></DT><DD>for the Intel Pentium4 CPU with 64-bit extensions, MMX, SSE, SSE2 and SSE3</DD>
+</DL>
+before you compile. This will allow processor specific schedulization optimizations
+and allow instruction sets such as MMX and SSE to be used.
+</P>
+
+<P>For the best performance, you may wish to modify the compile options in 
+<CODE>libs/libavcodec/libavcodec.pro</CODE>, and <CODE>libs/libavformat/libavformat.pro</CODE> as well,
+and include <TT>-mfpmath=sse</TT> in the compile options, if your processor supports SSE instructions.</P>
 
 <H2><A NAME="ss5.2">5.2</A> <A HREF="mythtv-HOWTO.html#toc5.2">Building LAME</A>
 </H2>