Save the Raptor's BlackBird model, most of them are in the sky with the Talos II being near the stratosphere.... In any case, after investigating a lot, in hopes of finding the best arch manual from IBM for our G4 and G5, I found this:
wiki.raptorcs.com
According to that, the G5 series (ppc970) complies with the PPC arch 2.01.2 and POWER ISA 2.03, but nowhere to be seen is the G4 series (74xx), after searching I can say that Motorola basically was on his own game with the G4, destined to the mainstream public, while IBM kept his presence unaltered in the server space with their POWER4, Motorola never seemed to care about ISA compliance, usually implementing their own instructions plus the ones present in the official release, so, as life is too short to get stuck with details.. The best manual overall for our machines is the 2.02 version:
Things to, more or less, expect:
•The older the PowerMac, the less instructions and features it will have (unless a CPU upgrade is installed)
•G4s (made by Motorola and later Freescale) usually don't give a damm about complying with IBM's official ISA implementation, usually adding (and perhaps removing?) Features from it.
•G5s (made by IBM because Motorola couldn't keep up, or so I believe) comply with IBM's reference, but the newer the PowerMac G5, the more recent the manual version you should use, topping at the POWER ISA v2.03 with the PPC970MP's (aka PM G5 quad) Altivec engine:
According to the Linux kernel documentation, the altivec present in the PPC970MP is better documented in the 2.03 version, also they establish that the CELL Broadband Engine (PS3 processor, in this case, they mean it's Power Processor Element, not to be confused with the Cell's Synergistic Processing Element) has features present in both the 2.02 and the 2.03 version (also specifying that it's the altivec version which is better documented in this version); the "similarities" between the PPC970/G5 and the Cell's PPE would explain why Hideo Kojima used G5s quad to develop MGS4 for the PS3.
