On Sat, Jan 10, 2015 at 12:17 PM, Andy Lutomirski <[email protected]> wrote:
>
> I asked this once, and someone told me that push/pop has lower
> throughput. I find this surprising.
It was true for some AMD CPU's in particular. One insn/cycle vs two.
I personally would be very happy to go back to push/pop sequences.
Even without a fancy stack engine like Intel has done for a while,
even *simple* cores can generally pair pushes and pops. I think the
original Pentium already had a special magic pairing logic to pair
pushes and pops despite both instructions using %esp. It's a common
and fairly trivial special case, and the fact that a few AMD
microarchitectures didn't do it is likely not really a good reason to
avoid repeated push/pop instructions.
Linus
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