No laughing  :lol:, but I was wondering (just a little bit) about this,
someone said to me - IF I remembered / heard it correct:

Somebody told me years ago (from this forum) that the GP registers
was something that the CPU didn't use anymore, that it was somewhat
outdated, and the CPU could handle the instructions without them via
pipelines or some other way ???

This seems totally weird, and I just want you guys to tell me that I must
have completely misunderstood the whole thing  :D


The SharK
Posted on 2007-12-29 12:50:22 by The SharK
Must be mixed information. The GPRs still physically exist on the x86, getting rid of them would render the x86 useless since "backwards compatibility" would no longer matter.

In fact, on the x86-64, they have been increased in size and number.
Posted on 2007-12-29 12:54:26 by SpooK
I think you have misunderstood things a bit :)

The general-purpose registers (which are very limited in number) are internally, on any recent CPUs, aliased/shadowed onto a (much higher) number of internal registers. And there's all kinds of other things involved, like speculative/out-of-order execution, retirement, dependency chains et cetera. Complex stuff.

Agner Fog probably mentions this stuff in his optimization manuals.
Posted on 2007-12-29 12:55:09 by f0dder