(SIMD) Optimized multi-byte chunk scanning

[Cecil Ward via Digitalmars-d-learn]

On Friday, 25 August 2017 at 18:52:57 UTC, Nordlöw wrote:
> On Friday, 25 August 2017 at 09:40:28 UTC, Igor wrote:
>> As for a nice reference of intel intrinsics: 
>> https://software.intel.com/sites/landingpage/IntrinsicsGuide/
>
> Wow, what a fabulous UX!

The pcmpestri instruction is probably what you are looking for? 
There is a useful resource in the Intel optimisation guide. There 
is also an Intel article about speeding up XML parsing with this 
instruction, but if memory serves it's really messy - a right 
palaver. A lot depends on how much control, if any you have over 
the input data, typically none I quite understand.

Based on this article,
     https://graphics.stanford.edu/~seander/bithacks.html
I wrote a short d routine to help me learn the language as I was 
thinking about faster strlen using larger-sized gulps. The above 
article has a good test for whether or not a wide word contains a 
particular byte value somewhere in it. I wrote a
    bool hasZeroByte( in uint64_t x )
function based on that method.

I'm intending to write a friendlier d convenience routine to give 
access to inline pcmpestri code generation in GDC when I get 
round to it (one instruction all fully inlined and flexibly 
optimised at compile-time, with no subroutine call to an 
instruction).

Agner Fog's libraries and articles are superb, take a look. He 
must have published code to deal with these C standard library 
byte string processing functions efficiently with wide aligned 
machine words, unless I'm getting very forgetful.

A bit of googling?