Overview
In MMIO, specific ranges of physical addresses are reserved for hardware devices rather than RAM. When the CPU reads from or writes to these addresses, the request is routed to the device instead of the memory controller.
Advantages
- Simplicity: No need for special I/O instructions; standard load/store instructions work for everything.
- Flexibility: Allows for more complex interactions with devices using the full power of the CPU's instruction set.
Disadvantage
Reduces the amount of address space available for actual RAM (though this is less of an issue in 64-bit systems).