In 2015....

DX arbitrary-precision integer arithmetic extensions Intel recently added

They are still working on making CPUs that can do arithmetic. Why not calculus already? I had a pretty hard time in my calculus class and I’m a human! Good luck with the integral calculus, CPUs, you're gonna need it.

Those ADX extensions are pretty lame. They include

- multiplication without affecting the flags
- add-with-carry affecting only carry flag
- add-with-carry using overflow flag as a carry flag

It's not the awesomeness that a REP ADD/ADC/SUB/SBB/etc.S{B,W,D,Q} would be:

; esi = source bignum
; edi = destination bignum
; ecx = size in dords
rep addsd
That would be a real "arbitrary-precision integer arithmetic extension".