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Instruction Set Design       

One of the most interesting, and most analyzed, aspects of computer design is instruction set design. The instruction set defines the functions performed by the CPU. The instruction set is the programmer's means of controlling the CPU. Thus programmer requirements must be considered in designing the instruction set.

Most important and fundamental design issues:

  Operation repertoire : How many and which operations to provide, and how complex operations should be.
  Data Types : The various type of data upon which operations are performed.
  Instruction format : Instruction length (in bits), number of addresses, size of various fields and so on.
  Registers : Number of CPU registers that can be referenced by instructions and their use.
  Addressing : The mode or modes by which the address of an operand is specified.

 
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