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Unformatted text preview: Separate I/O mapped processors. An example of I/O mapped processors are Intel x86 processors. The disadvantage of full address decoding is a large amount of hardware is required, see the following example 15 inverters 2 8-input NAND gates 1 NOR gate ce & VMA = 0 for addresses 0000h-0FFFhex , the additional locations where ce goes low is called mirror / aliasing of the memory space Separate I/O mapped processors have special I/O instructions such as: IN address OUT address To access I/O in a memory-mapped processors the same instructions are used as for memory, example mov R1, label Memory-mapped I/O can always be added to a Separate I/O processors. Design a 16-Bit output port at 0xFFFF...
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- Spring '11
- X86, Howard Staunton, Separate I/O, Separate I/O space