970 may be a bad example in that it can't actually bring itself up -- it requires an external controller to configure it at power-up. So whatever the external controller programs into the PC is where it starts.
970 always starts at HIOR|0x00100.
I don't see any mention of an initial PC value in the 970 user manuals.
For way more detail than you ever wanted to know of the 970 POR process, see for example the "970MP Power On Reset" application note. The relevant thing here is that the POR state machine instruction that starts the CPU core is SRESET -- and that is described in the UM just fine. Segher
