What are the advantages and di

The advantage of supporting memory-mapped I/O to device control registers is that it eliminates the need for special I/O instructions from the instruction set and therefore also does not requine the enforcement of protection rules that prevent user programs from ex-ecuting these I/O instructions.The disadvantage is that the resulting flexibility needs to be handled with care;the memory translation units need to ensure that the memory addresses associated with the device control registers are not accessible by user programs in order to ensure protection.