Messages in this thread | | | From | insecure <> | Subject | Re: nasm over gas? | Date | Wed, 10 Sep 2003 00:37:59 +0300 |
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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 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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