MSB0 is convention in basically all IBM documentation (including PowerPC/Power Architecture stuff), hence all the Freescale/NXP PPC manuals follow.
The main practical problem with MSB0 is that you need to consider the width of whatever field or register you're looking at to work out the correct bit shift.
The main practical problem with MSB0 is that you need to consider the width of whatever field or register you're looking at to work out the correct bit shift.