Re: Challenge: write a really really small front() for UTF8

[Piotr Szturmaj]

W dniu 2014-03-25 11:42, dennis luehring pisze:

Am 25.03.2014 11:38, schrieb Nick Sabalausky:

On 3/25/2014 4:00 AM, Iain Buclaw wrote:

On 25 March 2014 00:04, Daniel N <u...@orbiting.us> wrote:

On Monday, 24 March 2014 at 12:21:55 UTC, Daniel N wrote:

I'm currently too busy to submit a complete solution, but please
feel free
to use my idea if you think it sounds promising.

I now managed to dig up my old C source... but I'm still blocked by
dmd not
accepting the 'pext' instruction...

1) I know my solution is not directly comparable to the rest in this
thread(for many reasons).
2) It's of course trivial to add a fast path for ascii... if desired.
3) It throws safety and standards out the window.

4) It's tied to one piece of hardware.

No Thankee.

void doStuff() {
      if(supportCpuFeatureX)
          doStuff_FeatureX();
      else
          doStuff_Fallback();
}

  > dmd -inline blah.d

the extra branch could kill the performance benefit if doStuff is too small

void function() doStuff;

void main() {
    auto supportCpuFeatureX = detectCpuFeatureX();

    if (supportCpuFeatureX)
        doStuff = &doStuff_FeatureX;
    else
        doStuff = &doStuff_Fallback;
}