[OpenBIOS] How does one use the partition access functions

I see there are functions for accessing partition info in
modules/mac-parts.[ch] among others.  I do not see any of the code using
any of these functions however.

I am trying to fix booting on powermac's under qemu so that it actually
looks at each partition entry and determines if it is flagged as
bootable, and if so looks at the load size and load address specified
there and boots that.

The idea is to replace the broken quik boot code, with something that
actually does what the boot loader says to do, not what the openbios
assumes it wants to do.

Does anyone have any hint as to how to actually use these nice partition
access functions so I can look at each partition table entry until I
find the bootable one (if any)?