Re: [Help-gsl] Use of assembler code in matrix get element functions. Could be useful?

[Thomas Weber]

On Sat, Oct 23, 2010 at 10:36:00AM +0200, José Luis García Pallero wrote:
> Hello,
> First of all I should say that I don't know nothing about assembler
> programming, so this is only a question.
> In gsl_matrix_get functions the code that calculates the position of
> an element in the storing vector is 'i * m->tda + j', that is a
> product plus an addition. Could be a speed improving the
> implementation of these operations in assembler via the asm() gcc
> facilities? It could be programmed in assembler for x86 machines (so
> these are the most common) and in standard C for the others.

I suggest having a look at 
http://dl.fefe.de/optimizer-isec.pdf
first. 

Quote from it (page 38):
 - Using the inline assembler is hard
 - Most people can’t do it
 - Of those who can, most don’t actually improve performance with it

        Thomas