extreme mem usage under amd64 arch ?
gurney_j at resnet.uoregon.edu
Sat Apr 8 06:05:59 UTC 2006
Astrodog wrote this message on Sat, Apr 08, 2006 at 13:36 +0800:
> On 4/8/06, Oliver Fromme <olli at lurza.secnetix.de> wrote:
> > I guess this is the most important reason: If ints were 64
> > bits, there would be no easy way to handle 32 bit entities.
> > Not being able to handle 32 bit objects with a native data
> > type whould be a major problem, especially for an OS kernel,
> > I think.
> Can an AMD64 processor actually handle 32 bits of data natively, or
> does it just knock off the last 32 bits of a 64-bit version, when its
> not in long mode?
yes, it can... infact it defaults to 32bits unless a prefix is
provided to access 64bit registers... (assuming a mode that 64bit
registers are accessable).. Though as w/ most processors, the upper
32bits are still around, just on 32bit operations they are ignored...
John-Mark Gurney Voice: +1 415 225 5579
"All that I will do, has been done, All that I have, has not."
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