CS 25000 Lecture Notes - Lecture 16: Register File, Basic Block, Operand

• School: Purdue University
• Department: Computer Sciences
• Course: CS 25000
• Professor: Adams George

Document Summary

Pipeline hazards: hazard a situation in pipelining when the next instruction cannot execute in the following clock cycle, types, structural. Arise when there is insufficient hardware (structure) to support all combinations of instruction in overlapped execution: hardware cannot support the combination of overlapped instructions in the same clock- cycle, solution: build hardware to support all combinations, control. Instruction sets can be designed to be easier to pipeline for circuit designers. Predict the next instruction: guess next_instruction_address, doesn"t stall pipeline when guess is correct, when incorrect, must, nullify instructions that were incorrectly, fetch correctly. Prediction has a payoff in units of time saved: positive payoff when correct; negative when incorrect. Predict based on branch history: dynamic branch prediction guess based on past branch behavior, update predictions as program executes. 1 bit of history; changes prediction after 1 misprediction. Dependence: dependence is a property of a program whereby a fixed sequential relationship exists between actions of the code.