[gentoo-sparc] 64-bit gentoo-sparc, how to make it happen?

[Zhang Weiwu]

I have been using gentoo linux on my ultra-sparc U2 and U5 for two
years, untill very recently I learnt the gentoo Linux is actually not
64-bit (it is 32-bit).

The U2 gets broken after I upgraded OBP (when I tries Solaris 10, it
prompted OBP is 32-bit OBP, I must upgrade to 64bit, then I did it, then
this U2 never boots up again). I have the remaining U5 box serving as
print server, it simply run out of CPU power (a single A4 brochure
printing uses up CPU and caused very slow printing). I think I can run
the machine in 64-bit mode, recompile related packages in 64-bit
executable to regain some speed.

I tried to adjust C-flags:

CFLAGS="-O2 -m64 -mcpu=ultrasparc -fomit-frame-pointer -pipe"
(added -m64)

then emerge a package, get this error:

checking whether the C compiler (gcc -O2 -m64 -mcpu=ultrasparc
-fomit-frame-pointer -pipe ) works... no

I think perhaps it is not possible to compile anything in 64-bit
executable when the kernel itself is running in 32-bit mode. Perhaps it
is not possible to run 64-bit code on 32-bit kernal at all (if this
sounds obvious, I admit I am a newbie). So what should I do? Should I
try to compile a kernel with -m64 first? Then there comes another
question: can 32-bit OBP loads 64bit kernel? I don't know if I have 64
OBP at all (and don't know how to tell it), my other U2 has had 32bit
OBP, that's for sure.

and even if I try to compile a 64-bit kernel, that may as well not
possible because it seems gcc refuse to run with -m64 (the error message
above).

Besides, is 64-big executable much faster then 32-bit executable?

P.S. I bet there must be an article somewhere on the Internet telling
how to get 64-bit linux running on sparcs, only that I didn't find it.

-- 
gentoo-sparc@g.o mailing list