On Wed, May 03, 2006 at 01:45:59PM -0400, Jeremy Huntwork wrote: > > Erm, perhaps we're reading the above differently. On x86 -march implies > -mtune so a combination of -march and -mtune isn't necessary. I'm not > quite clear on what else -march gives you that -mtune doesn't, but > everything -mtune does, -march does. Also, we definitely don't want to > build specifically for pentium3. I've used the LiveCD on several pentium > IIs and it works great.
march dictates what instruction sets to use. mtune tunes the code to run on a given arch. setting mtune to something newer than march will allow it to optimize to that level but without overriding the instruction set dictated by march. If mtune is an older arch than march then that would not do anything (assuming the compiler even allowed it), but mtune can be a newer arch than march. So you get code optimized for pentium3 (which is a nice middle ground) but without any instructions not present in the 486 instruction set. -- Archaic Want control, education, and security from your operating system? Hardened Linux From Scratch http://www.linuxfromscratch.org/hlfs -- http://linuxfromscratch.org/mailman/listinfo/livecd FAQ: http://www.linuxfromscratch.org/faq/ Unsubscribe: See the above information page
