Gentoo Archives: gentoo-user

From: Andy Wilkinson <drukargin@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] i486
Date: Tue, 23 Nov 2010 14:37:34
Message-Id: 4CEBD143.3010907@gmail.com
In Reply to: [gentoo-user] i486 by James
1 On 11/22/2010 01:02 PM, James wrote:
2 > Hello,
3 >
4 > I want to set up a AMD AthlonXP on Compact
5 > Flash, just like I do my old pentium & i586 systems.
6 > I'd really like to be able to move 4G Cf cards
7 > (set up generically) between old pentium,
8 > k6, i586, p4 and AthlonXP systems. (that's the goal
9 > not performance, optimized for small binaries).
10 >
11 > OK, so I'm using ext2 on a 4 G CF.
12 >
13 > I want a universal /etc/make.conf file
14 > that will work on old hardware all the way
15 > up to a p4 (32bit) system, and on AMD
16 > (AMD Athlon(TM) XP 2400+)
17 >
18 > So take and look and tell me what I should
19 > change and why. OK?
20 >
21 >
22 > MARCH =???
23 >
24 > CHOST="i486-pc-linux-gnu"
25 > CFLAGS="-Os -march=??? -pipe -fomit-frame-pointer"
26 > CXXFLAGS="${CFLAGS}"
27 > PORTAGE_NICENESS="1"
28 >
29 > MAKEOPTS="-j2"
30 > USE="-* -nls mmx ncurses ssl crypt berkdb tcpd pam perl pcre \
31 > python readline zlib bzip2 nptl nptlonly syslog"
32 >
33 > Any suggestions on flags are most welcome!
34 > Ideas are most welcome!
35 >
36 >
37 > James
38 >
39 >
40 If this is one drive to run on all of them, -march=pentium -mmmx (if all
41 of your CPUs have mmx) will probably work. If the oldest stuff you've
42 got is p4, athlon-xp era, you might be able to get a bit newer... but
43 you'd need to compare the literal flags turned on by something like
44 -march=pentium3 and -march=athlon-xp (you can't use pentium4 because it
45 includes SSE2 which Athlon XP doesn't necessarily support).
46
47 You can check what flags gcc picks with:
48
49 echo | gcc -dM -E - -march=$MARCH
50
51 It's not super straightforward to look at, but it's the only way my
52 googling has found to actually show all of the flags turned on by an
53 -march or -mtune option.
54
55 -Andy