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64 bit code on a 32 bit OS

Started by thomas_remkus, October 22, 2007, 01:47:22 PM

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thomas_remkus

October 22, 2007, 01:47:22 PM
Is it possible to install a 32 bit OS on a 64 bit machine ... then access the 64 bit registers while in 32-bit land?

BogdanOntanu

#1
October 22, 2007, 03:23:41 PM
No.
Ambition is a lame excuse for the ones not brave enough to be lazy.
http://www.oby.ro

Mark Jones

#2
October 22, 2007, 03:34:27 PM
...But the 64-bit OS does support native 32-bit modules, correct? Probably at an abstraction layer or something.
"To deny our impulses... foolish; to revel in them, chaos." MCJ 2003.08

TNick

#3
October 22, 2007, 04:18:18 PM
Yes.

:)

Rockoon

#4
October 22, 2007, 04:35:22 PM
Quote from: Mark Jones on October 22, 2007, 03:34:27 PM
...But the 64-bit OS does support native 32-bit modules, correct? Probably at an abstraction layer or something.

Microsoft calls its abstraction layer Windows On Windows (WOW64)


I do not believe that a 32-bit program running under WOW64 can load and call 64-bit DLL's .. can anyone confirm?
When C++ compilers can be coerced to emit rcl and rcr, I *might* consider using one.

Vortex

#5
October 22, 2007, 05:21:46 PM
Thomas,

It would be good to access the 64-bit registers in the 32-bit environment for optimization purposes but probably that's not possible.

Rockoon

#6
October 22, 2007, 06:57:39 PM
No probably about it - the x86-64 registers are not addressible while in 32-bit mode .. this includes the extended SSE register set (xmm8 .. xmm15)
When C++ compilers can be coerced to emit rcl and rcr, I *might* consider using one.
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