[Openmcl-devel] string handling question

Andrew P. Lentvorski, Jr. bsder at mail.allcaps.org
Tue Nov 9 21:36:25 UTC 2004


On Nov 9, 2004, at 7:36 AM, alex crain wrote:

> For example,
>   (FIND #\s "mystring")
> eventually boils down to
>   (dovector (a "mystring")
>                     (when (eq a #\s) (return a)))
> but some implementations of strchr are smarter then that and would do 
> things in 4 or
> 8 byte chunks.
>
> Since I'm working on an OpenMCL editor, implementation dependence is 
> not a problem.

Personally, I really would not walk this path.

Unless you preload the cache with the constant string, the time 
required to pull that string from main memory will more than dominate 
the time to loop over it for small string lengths.

In addition, a generic loop unrolling optimization would be useful to 
OpenMCL, in general.  Although, it may already exist for certain levels 
of optimization.

What is the larger context problem that you are trying to solve?

-a




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