FreeBSD 6.2, rebuild. NO-MMX, NO-SSE?

Kris Kennaway kris at obsecurity.org
Mon Jan 15 20:21:13 UTC 2007


On Mon, Jan 15, 2007 at 08:52:04PM +0100, Daniel Tourde wrote:
> Hello,
> 
> Yesterday I rebuit FreeBSD 6.2 using CPUTYPE=pentium4 and the classic 
> procedure described in the manual.
> The machine (Inspiron 9400) is fast but I saw at certain moments something 
> like "NO-MMX, NO-SSE" (some flags or variables) during the compilation 
> process. I thought then "How come? What a pity not to use these 
> instructions".
> 
> Can someone tell me what it was and if it is really supposed to be like this? 
> My roots are in Gentoo Linux where it is possible to get the maximum out of a 
> processor when building a system from scratch by using properly certain C and 
> C++ flags.
> 
> I am pretty sure the same is possible with FreeBSD, however these 
> aforementionned flags raised some questions in my mind... ;)
> 

Yes, it's supposed to be that way.  Certain parts of the FreeBSD
system cannot use MMX or SSE instructions (e.g. the boot loader) but
it's okay since they are absolutely not performance critical.

Kris
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