Can you shrink it further?

[Stefan Koch via Digitalmars-d]

On Tuesday, 11 October 2016 at 14:49:28 UTC, Matthias Bentrup 
wrote:
>
> This is the result I'd like to get, but I can't find a way to 
> write it without inline assembly :(
>
> void popFrontAsmIntel(ref char[] s) @trusted pure nothrow {
>   immutable c = s[0];
>   if (c < 0x80) {
>     s = s[1 .. $];
>   } else {
>     uint l = void;
>     asm pure nothrow @nogc {
>       mov EAX, 1;
>       mov BL, 0xf8-1;
>       sub BL, c;
>       cmp BL, 0xf8-0xc0;
>       adc EAX, 0;
>       cmp BL, 0xf8-0xe0;
>       adc EAX, 0;
>       cmp BL, 0xf8-0xf0;
>       adc EAX, 0;
>       mov l, EAX;
>     }
>     s = s[l <= $ ? l : $ .. $];
>   }
> }

This takes 180us.
Baseline takes 124us.