Date: Tue, 09 Apr 2002 01:20:23 +0200 From: Michael Nottebrock <michaelnottebrock@gmx.net> To: Peter Leftwich <Hostmaster@Video2Video.Com> Cc: FreeBSD Questions <FreeBSD-Questions@FreeBSD.ORG>, FreeBSD Ports <FreeBSD-Ports@FreeBSD.ORG> Subject: Re: gcc -O -mcpu=i686 -howtooverride=486? Message-ID: <3CB225B7.4090405@gmx.net> References: <20020408140315.J8518-100000@66-75-1-142.san.rr.com>
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Peter Leftwich wrote:
> My question is the following-- It seems like my /etc/make.conf file (which
> I think I either mv'ed or cp'ed from /usr/local/etc/make.conf) is getting
> ignored as far as the "CPUTYPE=i686" flag goes. How do I remedy this?
>
> I have been editing the various "Makefile" files, overriding the usual "-O
> -m486" with "-O -mcpu=i686" (what is -march by the way?) but my extended
> question is the following-- Does the -mcpu flag that mean [paraphrase-ically]
> "use i686 instructions for the compile process" or does it mean "compile
> some binaries with i686 smartness built into them?" Know-whuht-eye-mean?
CPUTYPE= sets -march, not mcpu.
From the gcc documentation (i386-specific):
----snip
-mcpu=cpu type
Assume the defaults for the machine type cpu type when scheduling
instructions. The choices for cpu type are:
`i386' `i486' `i586' `i686'
`pentium' `pentiumpro' `k6'
While picking a specific cpu type will schedule things
appropriately for that particular chip, the compiler will not generate
any code that does not run on the i386 without the `-march=cpu type'
option being used. `i586' is equivalent to `pentium' and `i686' is
equivalent to `pentiumpro'. `k6' is the AMD chip as opposed to the Intel
ones.
-march=cpu type
Generate instructions for the machine type cpu type. The choices for cpu
type are the same as for `-mcpu'. Moreover, specifying `-march=cpu type'
implies `-mcpu=cpu type'
----snip
--
Michael Nottebrock
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