What do you mean by instruction pipelining, Computer Engineering

Assignment Help:

After considering instruction execution let's now describe a concept which is very popular in any CPU implementation. This conception is instruction pipeline. 

To extract better performance as said earlier instruction execution can be done through instruction pipeline. The instruction pipelining includes decomposing of an instruction execution to some pipeline stages. Some of the common pipeline phases can be instruction fetch (IF), instruction decode (ID), operand fetch (OF), execute (EX), store results (SR).  An instruction pipe caninclude any combination of such stages. A main design decision here is that instruction stages must be of equal execution time.

A pipeline allows overlapped execution of instructions. So during the course of execution of an instruction, following can be a scenario of execution.

2046_What do you mean by INSTRUCTION PIPELINING.png

                                                    Figure: Instruction Pipeline                            

Please note following observations about above figure:

  • Pipeline stages are just like steps. So a step of the pipeline is to be complete in a time slot. Size of the time slot will be administered by the stage taking maximum time. So if the time taken in different stages is almost similar we get the best results.
  • First instruction execution is completed on completion of 5th time slot thoughsubsequently in every time slot the next instruction gets executed. Thus in ideal conditions one instruction is executed in pipeline in each time slot.
  • Please note that after 5th time slot and afterwards the pipe is full. In the 5th time slot the phases of execution of five instructions are:

SR (instruction 1) (Requires memory reference),

EX (instruction 2) (No memory reference),

OF (instruction 3) (Requires memory reference),

ID (instruction 4) (No memory reference),

IF (instruction 5) (Requires memory reference),

The Pipelining Problems:

  • On the 5th time slot and afterwards there can be a memory or register conflict in the instructions which are performing memory and register references that is various phases may refer to same memory/registers location. This will yield in slower execution instruction pipeline which is one of the higher number instruction has to wait till lower number instructions completed effectively pushing whole pipelining by one time slot.
  • Another significant situation in Instruction Pipeline can be the branch instruction. Presume that instruction 2 is a conditional branch instruction then by the time the decision to take branch is taken (at time interval 5) three more instructions have already been fetched. So if the branch is to be taken then whole pipeline is to be emptied first. So in such cases pipeline can't run at full load.

 


Related Discussions:- What do you mean by instruction pipelining

How do you add a developer to a trusted publishers list, Whenever a develop...

Whenever a developer is signing into the code project you will have three options they are disable the macro, enable the macro and explicitly trusting the publisher. You can trust

Discuss different mode of centralized stored program control, Explain SPC. ...

Explain SPC. Also discuss the different modes of Centralized SPC In stored program control systems, set of instructions or a program to the computer is stored into its memory a

C, "Super ASCII", if it contains the character frequency equal to their asc...

"Super ASCII", if it contains the character frequency equal to their ascii values. String will contain only lower case alphabets (''a''-''z'') and the ascii values will starts from

What is time out mechanism, What is time out mechanism. If one unit is ...

What is time out mechanism. If one unit is faulty the data transfer will not be done. Such an error can be detected using time out mechanism which makes an alarm if the data tr

Determine the fastest logic, Which of the fastest logic: TTL, ECL, CMOS and...

Which of the fastest logic: TTL, ECL, CMOS and LSI ? Ans. The fastest logic family of all logic families ECL. High  speeds  are  possible  in  ECL  since the  transistors  a

Why did some plug-ins disappear for 0.99.19, Some of the plug-ins have prov...

Some of the plug-ins have proven unstable. These have been moved into a split download, which should be available anywhere you got the GIMP, in the file gimp-plugins-unstable-VERSI

Define thread cancellation and target thread, Define thread cancellation & ...

Define thread cancellation & target thread.  The thread cancellation is the task of terminating a thread before it has done. A thread that is to be cancelled is often referred

Main strength of ascii, Q. Main strength of ASCII? One such standard co...

Q. Main strength of ASCII? One such standard code which enables language encoding that is popularly used is ASCII (American Standard Code for Information Interchange). This cod

Program in c, addition c program for token separation

addition c program for token separation

Write an interrupt routine to handle division by zero, Q. Write an interrup...

Q. Write an interrupt routine to handle 'division by zero'? This file can be loaded just like a COM file though makes itself permanently resident until the system is running.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd