Port amigappc

[Frank Wille <frank%phoenix.owl.de@localhost>]

Hi!

I'm currently analyzing and experimenting with the amigappc port, to get a
better understanding for kernel-programming.

After many years amigappc compiles and links again, but I have a problem
with the exception handlers from powerpc/powerpc/trap_subr.S: They are using
the "bla" instruction to branch into the actual kernel, which forces the
kernel to reside in a region from 0x00000000 to 0x03ffffff or 0xfc000000 to
0xffffffff.

Unfortunately Amigas have their Fast-RAM between 0x07000000 and 0x0fffffff,
which is out of range. What would be the most elegant solution?

Maybe implement a stub near the exception address space, which does
something like:

s_trap:
    bl  s_trap2
    .long   s_trap_kernel   # R_PPC_ADDR32 reloc
s_trap2:
    mflr    r11
    lwz r11,0(r11)
    mtlr    r11
    blr


-- 
    _  Frank Wille (frank%phoenix.owl.de@localhost)
 _ //  http://sun.hasenbraten.de/~frank/
 \X/   Phx @ #AmigaGer