[Vm-dev] linux 64bit vm running a 32 bit images - networking vm crash

bryce at kampjes.demon.co.uk bryce at kampjes.demon.co.uk
Fri Jun 1 17:47:32 UTC 2007

tim Rowledge writes:
 > >> Somebody is going to have to explain this to me. Why would you have
 > >> to "change into a 32bit environment" ?
 > >
 > > On a 64-bit machine, a 32-bit VM has to use the appropriate runtime
 > > libraries.
 > Oh, duh. '64 bit' makes noises in my head about 64 bit OOPs. Never mind.

There's also the possibility that the AMD64 instruction set is
faster than AMD32 especially if you're using a 32 bit image so
are not paying for extra memory bandwidth for each oop. The reason
is increasing the number of registers from 8 (6-7 usable) to 16.

This may not matter for the interpreter given branch mispredicts
due to decoding.


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