SIMD support...

[Brad Roberts]

On Fri, 6 Jan 2012, Walter Bright wrote:

> On 1/6/2012 11:16 AM, Brad Roberts wrote:
> > However, a counter example, it'd be a lot easier to write a memcpy routine
> > that uses them
> > without having to resort to asm code under this theoretical model.
> 
> I would seriously argue that individuals not attempt to write their own
> memcpy.
> 
> Why? Because the C one has had probably thousands of programmers looking at it
> for the last 30 years. You're not going to spend 5 minutes, or even 5 days,
> and make it faster.

Oh, I completely agree.  Intel has people that work on that as their 
primary job.  There's a constant trickle of changes going into glibc's 
mem{cpy,cmp} type routines to specialize for each of the ever evolving set 
of platforms out there.  No way should that effort be duplicated.  All I 
was pondering was how much cleaner much of that could be if it was 
expressed in higher level representations.  But you'd still wind up 
playing serious tweaking and validation games that would largely if not 
completely invalidate the utility of being expressed in higher level 
forms.  Probably.

Later,
Brad