[PLUG] 64-bit programming

Tyler F. Creelan creelan at engr.orst.edu
Sun Jun 16 05:45:44 UTC 2002


Carla -

There's an excellent paper on this topic, entitled "The myths and
realities of 64-bit computing" [1].

To summarize, the purpose of 64-bit computing is to provide a
64-bit address space, so you can use more than 4 GB of memory. A
64-bit processor will not by itself provide any increase in performance;
in fact, the performance of your program will be hurt slightly because
your pointers must occupy twice as much space in the cache, reducing the
hit ratio.

The ability to perform single instruction arithmetic on gigantic numbers
can also be useful, in some rare applications. Usually however, 64 bit
data operands are disabled in favor of 32-bit, again to free up the cache.

1. http://www.anandtech.com/guides/viewfaq.html?i=112


Tyler

____________________________
Tyler F. Creelan
College of Engineering
Oregon State University
http://www.cs.orst.edu/~creelan/

On Sat, 15 Jun 2002, Carla Schroder wrote:

> Any thoughts on programming for a 64-bit cpu like the Itanium, other than it
> sounds like a speech impediment? Are there practical reasons? Kylix is
> strictly IA32, and may someday support 64-bit cpus. Then again, maybe not.
> gcc of course has IA64 and Alpha support. I'm wondering does it really matter
> in these days of distributed computing and low-cost clusters and SMP, why
> complicate things by introducing yet another complication? Just string a herd
> a them IA32s together.
>
> Thanks,
> Carla
>





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