Mandriva and Unity Linux work on armv7 port
by Paulo César Pereira de Andrade
Hi,
In the past few days I made some changes to djdelorie's
bootstrap scripts to adapt it to mandriva, so, I believe I should
at least give some feeback :-)
I have built two chroots on two panda boards, one with
hardfp that should match current fedora, and another
using --with-float=softfp, as at least for now I think it
would be wiser for me, and available resources to
be able to use a large amount of armv5 packages
made by Matthew Dawkins, for Unity Linux.
Currently I am connecting to remote panda boards at
jbj.org, so, Jeff is providing the infrastructure (currently
I do not have access to armv7 hardware). The boards are
running:
Linux panda3.jbj.org 2.6.38.8-32.01.fc13.armv7l.omap #1 SMP PREEMPT
Tue Jun 14 22:12:54 EDT 2011 armv7l armv7l armv7l GNU/Linux
[root@panda3 /]# cat /etc/fedora-release
Fedora release 13 (Goddard)
So, for example (and sorry for long email) in fedora,
and my other bootstrap chroot, with objdump I see
the pattern:
00008b68 <__ieee754_atan2>:
8b68: e3a01000 mov r1, #0
8b6c: e3471ff0 movt r1, #32752 ; 0x7ff0
8b70: ec532b11 vmov r2, r3, d1
8b74: e3a00000 mov r0, #0
8b78: e0031001 and r1, r3, r1
8b7c: e3470ff0 movt r0, #32752 ; 0x7ff0
8b80: e1510000 cmp r1, r0
8b84: e1a0c003 mov ip, r3
8b88: e92d0030 push {r4, r5}
8b8c: ed2d8b10 vpush {d8-d15}
8b90: e1a05002 mov r5, r2
8b94: e24dd028 sub sp, sp, #40 ; 0x28
8b98: eeb08b41 vmov.f64 d8, d1
8b9c: eeb09b40 vmov.f64 d9, d0
8ba0: 0a000023 beq 8c34 <__ieee754_atan2+0xcc>
arguments in d0, d1
And in the alternate build I see the pattern:
00008d30 <__ieee754_atan2>:
8d30: e3a0c000 mov ip, #0
8d34: e347cff0 movt ip, #32752 ; 0x7ff0
8d38: e92d4030 push {r4, r5, lr}
8d3c: ed2d8b10 vpush {d8-d15}
8d40: e3a05000 mov r5, #0
8d44: ec432b18 vmov d8, r2, r3
8d48: e3475ff0 movt r5, #32752 ; 0x7ff0
8d4c: e003c00c and ip, r3, ip
8d50: e15c0005 cmp ip, r5
8d54: e24dd02c sub sp, sp, #44 ; 0x2c
8d58: e1a04003 mov r4, r3
8d5c: ec410b19 vmov d9, r0, r1
8d60: e1a05002 mov r5, r2
8d64: 0a000022 beq 8df4 <__ieee754_atan2+0xc4>
arguments in r0,r1,r2,r3
I did not do any performance measures so far, so
forgive me if the extra "vmov d#, r#,r#" or "vmov r#,r#, d#"
is too costly, but I think it should be worth the
compatibility with rpms for armv5 or earlier. It should
have been already discussed at fedora, but I really
do not know the real reason :-)
Also, as I am still in very early stages, and doing
experiments, so far I am using only the cross compiled
gcc, i.e.:
bash-4.2# gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/armv7l-mandriva-linux-gnueabi/4.6.1/lto-wrapper
Target: armv7l-mandriva-linux-gnueabi
Configured with:
/home/pcpa/bootstrap/rpmbuild/BUILD/gcc-4.6-20110722/configure
--prefix=/usr --build=i586-mandriva-linux-gnu
--host=armv7l-mandriva-linux-gnueabi
--target=armv7l-mandriva-linux-gnueabi --enable-werror=no --enable-cxx
--with-cpu=cortex-a8 --with-tune=cortex-a8 --with-arch=armv7-a
--with-float=softfp --with-fpu=vfpv3-d16 --with-abi=aapcs-linux
--enable-languages=c,c++ --enable-threads=posix --disable-libssp
--disable-libmudflap
Thread model: posix
gcc version 4.6.1 20110722 (Mandriva) (GCC)
But have already rebuilt some of the "bootstrap" mandriva
packages, rpm5, etc, as well as have packages built for
armv5 installed. This way, rebuilding for armv7 is an
"optimization", and have something to start with...
Thanks,
Paulo
