This is a long shot, and may come under fire as not being EE-enough of a question for this site, but what conditions will result in a PowerPC processor (e.g. Freescale 7448) taking a jump to address 0xfff00800? My reading of the family reference manual suggests this is a Floating-Point Unavailable Exception, but in talking to people it's been suggested this is a common place where programs go to die on a bad instruction decode. Assuming that's accurate is there any way to recover what the errant instruction was via poking and prodding with a JTAG debugger?
I don't know the architecture in question, but from general processor knowledge, could you not examine the stack to find the PC (or equivalent) from when the interrupt was triggered and look at the memory pointed to by that? You woudn't even really need JTAG - you could do it in the interrupt routine.