64-bit CPU

[Henry Spencer]

On Wed, 15 Sep 2004, Andrej Marjan wrote:
> x86-64 has many more registers, hence the performance improvement for 
> programs that don't need the extra addess space or 64 bit integer 
> computations.

That may not be the full story, though, because the Pentium and its
descendants have long had more registers internally than the architecture
officially specified.  They're internal temporaries, used for things like
pipelining, but some work at Bell Labs indicated that you can get quite
good code for those machines by slicing off a 32-word piece of memory and
pretending it's registers, because the "register renaming" trickery hidden
inside the hardware more or less makes it so.  (Code from compilers which
don't take this approach might not exploit the hardware fully, however.)

                                                          Henry Spencer
                                                       henry-lqW1N6Cllo0sV2N9l4h3zg at public.gmane.org

--
The Toronto Linux Users Group.      Meetings: http://tlug.ss.org
TLUG requests: Linux topics, No HTML, wrap text below 80 columns
How to UNSUBSCRIBE: http://tlug.ss.org/subscribe.shtml