x86 - x64 porting query

We have an application 开发者_运维技巧written in C/C++ code running on 32-bits windows with 32-bit Hardware. My question is that if we upgrade our hardware to 64-bit and keep our OS 32-bit, does my application need a port to 64-bit? If it requires, what benefits will be there on a 32 bit OS?

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Hardware doesn't count -- the OS does. Ergo:

• 32 bit hardware with 32 bit OS will run only 32 bit ports
• 64 bit hardware with 32 bit OS will run only 32 bit ports
• 64 bit hardware with 64 bit OS will run both 32 bit and 64 bit ports

The advantage of recompiling for 64 bit is access to more than 3GB ram and a speed increase if you operate on 64 bit datatypes or take advantage of compiler intristics (and a few others, but do not count on a immedate gain).

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If you keep the OS 32-bit, you must keep the app 32-bit, for many common values of OS. We, of course, cannot use telepathy to tell which OS you are using.