I&C SCI 51 Lecture Notes - Lecture 4: Operand, Instruction Set, Microcode
11 Dec 2016
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Document Summary
All instructions are directly executed by hardware. Maximize rate at which instructions are issued. Instruction represents control signals for datapath units. Only loads and stores should reference memory. Provide plenty of registers (at least 32) Each instruction execute in one clock cycle. Requires more instructions to complete each computation (than cisc) Sequence of internal cpu instructions that translates an isa instruction into multiple. If id ea of ex. If (instruction fetch): fetch an instruction from memory. Id (instruction decode): decode the instruction into control lines that feed into the components of the datapath. Ea (effective address): compute the memory location of an operand. Of (operand fetch): fetch data at the address computed in the previous (ea) stage. Ex (execute): alu performs the operation specified by the decoder onto the data operands, and store the result. If (instruction fetch): fetch an instruction from memory pre-fetch.
