Re: Using %cr2 to reference "current"

Martin Dalecki
2001-11-07T14:44:15Z

Alan Cox wrote:
>
> > somehow encouraged by the compiler comparisions between gcc and intel's
> > free compiler, which use the register passing for anything local
> > to the actual code, where the speed gains are up to 20% im currently
>
> I was under the impression intels compiler was profoundly non-free ?

Well it's free in terms of money, read: download and "personal usage"
blabla.
This doesn't deterr me from having a look at it ;-).
>
> > quite inclined to do the redo and finish the experiment.
> > BTW.> It's not just asm fixpus that have to be done for this
> > to work. For example all the c files with -fno-omit-frame-pointer
>
> 20% is a nice large number.

Yes I was impressed as well and twiddeling with compiler flags is
actually indicating that the calling convention stuff is one
of the main contributors to this. BTW.> The speed differences
can go up to 40% for floating point, OK this is irrelevant for
the kernel but it is showing very well that there is still
plenty of room for improvement.