On Monday, 16 May 2016 at 10:33:58 UTC, Andrei Alexandrescu wrote:
My understanding is also that 80-bit math is on the wrong side
of the tradeoff simply because it's disproportionately slow.
Speed in theory shouldn't be that big of a problem. As I recall
the FPU *was* a separate processor; Sending the instructions took
like 3 cycles. Following that you could do other stuff before
returning for the result(s), but that assumes you aren't *only*
doing FPU work. The issue would then come up when you are waiting
for the result after the fact (and that's only for really slow
operations, most operations are very fast, but my
knowledge/experience is probably more than a decade out of date).
Today I'm sure the FPU is built directly into the CPU.
Not to mention there's a whole slew of instructions for the x86
that haven't improved much because they aren't used at all and
instead are there for historical reasons or for compatibility.
jcxz, xlat, rep, and probably another dozen I am not sure just
off the top of my head.
Perhaps more processors and in general should move to a RISC
style instructions.
