x86-64 on i386 (was Re: Promoting i386 version over x86_64?)

[Chris Adams]

Once upon a time, Jeff Garzik <jgarzik at pobox.com> said:
> Running a 64-bit kernel with a 32-bit userland is a common practice on 
> non-x86 platforms, and non-Linux OS's.  For a lot of tasks, you simply 
> do not need 64-bit pointers and a 64-bit process address space.  Both 
> executable code and in-memory data structures tend to be smaller on 32-bit.

However, on x86, the 32->64 bit jump also gives a larger register set
and (IIRC) SSE (or SSE2?) on all chips, which allows better code
generation for all kinds of things.

The i386 architecture is register-starved compared to many other
architectures.
-- 
Chris Adams <cmadams at hiwaay.net>
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.