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>"the encoding hack that enables addressing of r8-r15 in the long mode is probably against one of Geneva conventions ..." Might you or anyone else have any lin

>"the encoding hack that enables addressing of r8-r15 in the long mode is probably against one of Geneva conventions ..." Might you or anyone else have any links or literature on what this hack is or how it works? >"the constant proliferation of control registers is vexing ..." I'm guessing this isn't referring to control registers proliferating on different of generations of CPUs at the discussion is about the ISA. Could you elaborate on how exactly they've proliferated?

Joker_vD 5y ago
> Might you or anyone else have any links or literature on what this hack is or how it works? Intel 64 and IA-32 Architectures Software Developer's Manual, volume 2, chapter 2.2.1 "REX Prefixes". I understand that there was literally no place in either opcode or ModR/M byte to squeeze in another bit, but still. As for control registers: we now have 9 "control registers", CR0 through CR8, and 4 of them are still reserved which kinda makes this whole "reserved" business seem pointless. And then, of course, there are MSRs, loads and loads of MSRs. In fact, there are so many of them that we now have a whole separate volume 4 of Intel SDM that is dedicated exclusively to them and is about 300 pages long. No doubt it will be 400 pages in the near future. Honestly, writing about this stuff feels like quoting from the "See Figure 1" doc.