Date: Tue, 29 Aug 2000 14:54:12 -0500 (CDT) From: Mike Meyer <mwm@mired.org> To: rob <europax@home.com> Cc: questions@freebsd.org Subject: CFLAGS -O, if I am running a 686, does it automatically target my cpu? Message-ID: <14764.5348.342064.352183@guru.mired.org> In-Reply-To: <74759745@toto.iv>
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rob writes: > I am curious about whether make automatically tells gcc to optimize to > my machine's cpu, a 686, or does it optimize to a 386? Reading though > the manuals, I can see that gcc can target a 686 or any other cpu, but I > have no idea what happens when I use make to compile my system or a > port. Rob. I vaguely recall that it optimizes for the *family*. However, the interesting part is found in the -mcpu documentation: the compiler will not generate any code that does not run on the i386 without the -march=cpu type option being used. So you're going to be running 386 instructions on your machine unless you set add a -march flag to the compile. On FreeBSD, you can set these in /etc/make.conf. Use CFLAGS for ports and other userland code, and COPTFLAGS for the kernel. <mike To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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