Compiling (was RE: [SPARCbook] re: linux on GX)

[Ari Heitner]

Just a further note:

SPARC has interesting backwards compatibility from the 64bit SPARCs to the
32bit ones.

In general user applications (stuff that you're not that obsessed for
speed over) are just compiled to work on v8's -- I steal plenty of
utilities and whatever else for my SB3 off of the Ultra's I use
day-to-day, and everything always works, except for library
compatibilities :(.

This is of course truly bizarre for a 64bit chip -- Merced sure won't run
i386 stuff natively (it'll have a separate P6 core for doing that). But
the Ultras have something called 32bit userland, which is for user-mode
apps. So the OS kernel has to be 64bit, but most of your apps don't have
to be -- and it doesn't make sense for them to be, since 64bit apps waste
a lot of memory on all those big pointers.

Your typical UltraSPARC Linux distribution -- say Debian UltraSPARC -- has
a kernel specially compiled with egcs64, the 64bit-specific compiler,
along with a _few_ userland apps compiled 64bit. Everything else is the
same as the standard Debian distro for 32bit SPARCs.

I of course find it tremendously amusing to run the same stuff on an
Ultra-60 and my SPARCStation 1+ :)

Ari Heitner
  DC: 703/5733512		CMU: 412/8622699
  www.singularity-software.com
"You know how your whole life flashes in front of your eyes before you die?
That's just gdb unwinding the call stack . . . "