At 6:20 PM +0200 4/22/05, R=E9mi Zara wrote:

> >> NetBSD/macppc OpenFirmware Boot, Revision 1.10
> >> (rzara@Ordinateur-de-Remi-Zara.local, Fri Apr 22 18:08:21 CEST 2005)
>file: 192.168.1.102,ofwboot.xcfnet_open: client addr: 192.168.1.10
>net_open: subnet mask: 255.255.255.0
>net_open: net gateway: 192.168.1.254
>net_open: server addr: 192.168.1.102
>net_open: server path: /data/export/macppc
>net_open: file name: ofwboot.xcf
>Using IP address: 192.168.1.10
>root addr=3D192.168.1.102 path=3D/data/export/macppc
>5087124+244504 [244576+226593]=3D0x588ed4
>  start=3D0x100000
>DEFAULT CATCH!, code=3DFFF00700
>  ok
>0 > .registers
>Client's Fix Pt Regs:
>  00 00000000 00692EFC 00000000 00692F0C 00693000 00000000 00E0F0BC
>0000001D
>  08 00692F2C 00692F30 FFFFFFFF 57000558 00000000 DEADBEEF DEADBEEF
>DEADBEEF
>  10 DEADBEEF DEADBEEF DEADBEEF DEADBEEF DEADBEEF DEADBEEF DEADBEEF
>DEADBEEF
>  18 DEADBEEF DEADBEEF DEADBEEF 00688ED4 00100000 00E0F0D1 DEADBEEF
>00E0F0BC
>Special Regs:
>     %IV: 00000700   %SRR0: 57001020   %SRR1: 00080000     %MQ: 00000000
>     %CR: 50000093     %LR: 0035725C    %CTR: 57000558    %XER: C000BE6F
>    %DAR: FFFFFF8B  %DSISR: 40000000   %SDR1: 00FE0000
>  ok

The LR indicates you're well into the kernel, but having OF catch the
exception suggests that the kernel's exception handlers have not been
properly installed.  The SRR0 is whacked, though.  That should be the
instruction address that caused the exception, and is well outside physical
memory unless this 7200 has 5*256M of memory, and the 7200 only supports
1G, according to the hardware note.

At the exception, try

%LR 10 dis

That'll give you the four instructions before and something like eight
after the bl or blrl instruction.  From there you can objdump -d the kernel
and locate the same instructions.  That'll narrow down where the jump off
occured.

If dis craps out, as it often does on early OF, try

%LR 10 - 20 dump

That will dump the memory raw from four instructions before the LR. You'll
have to break it down into four byte lengths to get the opcodes.

If it is of any help, I documented my efforts to port OpenBSD to Old World
Macs.

http://www.dialectronics.com/OldWorldMacs

It might contain some techniques to help you.  Also note that the kernel
will need to have several components modified, as the 7200 used an IC
called "Platinum" for video.  The stuff that attaches under Bandit will
probably work, though.

tim