Instruction pipelines, Computer Engineering

Instruction Pipelines

As discussed previous, the stream of instructions in the instruction implementation cycle, can be realized through a pipeline where overlapped implementation of different operations are performed. The process of implenting the instruction involves the following main steps:

  • Fetch the instruction by the main memory
  • Decode the instruction
  • Fetch the operand
  • Implement the decoded instruction

These four steps become the candidates for phases for the pipeline, which we state as instruction pipeline (It is given in Figure).

                                                471_Instruction Pipelines.png

                                                          Figure: Instruction Pipeline

While, in the pipelined implementation, there is overlapped implementation of operations, the four phases of the instruction pipeline will work in the overlapped manner. Firstly, the instruction address is fetched from the memory to the first phase of the pipeline. The first phase fetches the instruction and provides its output to the second phase. Whereas, the second phase of the pipeline is decoding the instruction, the first phase gets another input and provides the next instruction. When the first instructions have been decoded in the second phase, then its output is fed to the third phase. When the third phase is fetching the operand for the first instruction, then the second phase gets the second instruction and the first phase gets input for another instruction and so on. In this manner, the pipeline is implementing the instruction in an overlapped way increasing the speed of execution and throughput.

The situation of these overlapped operations in the instruction pipeline can be demonstrated through the space-time diagram. In Figure, firstly we show the space-time diagram for non-overlapped implementation in a sequential environment and then for the overlapped pipelined environment. It is clear from the two diagrams that in non-overlapped implementation, results are achieved only after 4 cycles while in overlapped pipelined implementation, after 4 cycles, we are receiving output after every cycle. Soon in the instruction pipeline, the instruction cycle has been deduced to ¼ of the sequential implementation.

                                      879_Space-time diagram for Non-pipelined Processor.png

                                                Space-time diagram for Non-pipelined Processor

                                    967_Space-time diagram for Overlapped Instruction pipelined Processor.png

                                              Space-time diagram for Overlapped Instruction pipelined Processor

Posted Date: 3/2/2013 7:06:09 AM | Location : United States







Related Discussions:- Instruction pipelines, Assignment Help, Ask Question on Instruction pipelines, Get Answer, Expert's Help, Instruction pipelines Discussions

Write discussion on Instruction pipelines
Your posts are moderated
Related Questions
Write a BASH/C shell script which takes name of one or more files as a command line argument, and prints the following information for each file: owner, number of words in the file

How many lists can a program can produce? Every program can produce up to 21 lists: one basic list and 20 secondary lists.  If the user makes a list on the next level (that is,

Array Processing We have seen that for performing vector operations, the pipelining concept has been taken. There is another method for vector operations. If we have an array o

Define the types Programmable logic devices? There are mostly three types PLDs. These are vary in the placement of fuses in the AND- OR array. 1. ROM- It has fixed AND array

Explain about the two services that are used to deal with communication. Message Service: Used by the application servers to change short internal messages, all system commu

Artificial Intelligence Agents: We introduced what we'll be conversation about in Artificial Intelligence and why those things are necessary. This discussion is of course abou

Working of compact disk: A CD is built from 1.2 mm thick, approximately all-pure polycarbonate plastic and its weighs is approximately 15-20 grams. From the core outward compo

33.A juice company manufactures one-gallon bottles of three types of juice blends using orange, pineapple, and mango juice. The blends have the following compositions: 1 gallon or

How is recursion handled internally? Internally, every recursive call to a function requires storing the intermediate values of the parameters and local variables in a run time

Question: (a) Provide types of computer systems and briefly describe each one. (b) With the help of example, explain the difference between open source software, freeware a