The Great Mr. Kurtz writes:
> > No one else is targetting
> > Apple PowerPC-based hardware (as far as I know) because of the
> > lack of documentation.
> 
> Hmmm.  I'm sure the PREP compliance stuff is out there.  After all, there 
> are two or three companies already building clones.  I've got a reference 
> manual on my shelf for the PPC 601/603/604/620 procesor.  It includes an 
> entire section on OS development for the PPC.  What other information do 
> you need?  Is it just stuff about Apple's implementation?  Talk to the 
> clone manufacturers.  They'd be a lot more likely to help.  :-)

Unfortunately, you need a lot more than a processor ref. manual to
write an OS, in the same way that you need a lot more than a processor
to build a computer.  That is what the PREP spec is for.
Unfortuantely, the PowerMacs are not PREP-compliant (as you point out
below, they are essentially quadras) and, apparently, Apple is less
than enthusiastic about divulging their technical details.  The clone
makers may or may not be bound by some sort of non-disclosure
agreement, but they'd be worth asking.

> Anybody put together a cross-compiler for PPC yet?  I was just thinking 
> if someone got an AIX copy of gcc (to get the right instruction set) and 
> patched it with the standard netbsd/mac68k includes with (possibly) some 
> tweaks to the big endian/litle endian stuff, could we at least get a 
> kernel that would work as a serial terminal in native mode?  At least 
> with the nubus PowerMacs, the internal architecture is nauseatingly 
> similar to the Quadras, but with a few changes in the memory management 
> and the display and its interface with the memory.

Last I saw, GCC and GAS could compile and assemble PPC code, but GNU
ld couldn't link it.  Has this changed in the latest binutils?  I
haven't checked.

If it does work, it would be immediately useful for MacOS development
too, since MacOS can run standard AIX XCOFF-format binaries (that is,
XCOFF format, but making MacOS, not AIX, traps.)

						Brian Johnson