memory mapped IO on a machine with 4 GB of RAM?

["Rajat Jain" <rajat.noida.india@xxxxxxxxx>]

Hi list,

I was wondering that if a machine has 4 GB of physical RAM, then how
will the devices map their registers to memory?

So if a device maps its registers in say memory address X, then will
that particular physical memory become inaccessible to the system?

Thanks,

Rajat

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