In an effort to figure out why qemu-system-ppc hangs at BootX when using
some emulated and KVM CPU’s, I suppose it would be good to enter some
breakpoints in the code.
I found some BootX sources at:
https://opensource.apple.com/tarballs/BootX/
Tho I’m not sure what versions correspond to which release of OS X?
And it’s not clear how to build them, tho I haven’t tried yet.
I found some info on BootX as well as some idea how to do what I’m
looking to do:
https://people.ffii.org/~zoobab/bh.udev.org/filez/apple/mac6100/BootX.pdf
*There are few other useful debugging tech- niques. Setting "auto-boot?"
to false will cause the system to enter the OpenFirmware User In-
terface by default. Changing kFailToBoot to 0 in include.tproj/sl.h will
alter BootX’s default be- havior on error, so that it will return to
Open- Firmware. Finally, calling Enter(), will cause BootX to drop back
into the OpenFirmware User **Interface. This can be used as a break
point. The "dumpl" word will dump some memory, by en- tering the
address, then the length, then "dumpl". By calling printf in BootX
immediately before En- ter(), the address can be easily determined, and
the variable can then be examined and altered from OpenFirmware. Finally
typing the "go" command will resume BootX’s execution. *
I noted when I boot from boot usb0/disk:3,\\:tbxi while holding
command+v BootX sends some info to the screen, seemingly via open
firware, while displaying the “Apple Logo” boot graphic. The info show
some of the boot process and what stage it’s loading” loading
mach_kernel’ “ loading the .mkext”
It would be nice to get this output going via Open Bios, if anyone has
any idea how I might be able to do that?