Re: nasm over gas?

[insecure <insecure@mail.od.ua>]

On Sunday 07 September 2003 22:30, Jamie Lokier wrote:
> Eric W. Biederman wrote:
> > Actually it is no as simple as that.  With the instruction that uses
> > %edi following immediately after the instruction that populates it you
> > cannot execute those two instructions in parallel.  So the code may be
> > slower.  The exact rules depend on the architecture of the cpu.
>
> I remember inserting a "nop" into a loop and it went significantly
> faster on a Pentium Pro :)

My example in _not_ a loop, far from it. That's the point.
GCC thinks everything is a loop.

> > If you concentrate on those handful of places where you need to
> > optimize that is reasonable.  Beyond that there simply are not the
> > developer resources to do good assembly.  And things like algorithmic
> > transformations in assembly are an absolute nightmare.  Where they are
> > quite simple in C.
>
> If we had enough developer resources to write the whole thing in good
> assembly, then for _sure_ we'd have enough to write a perfect compiler!

Peace, Jamie. I do _not_ advocate using asm anywhere except speed critical
code.
-- 
vda