Instruction issue degree, Computer Engineering

Assignment Help:

Instruction Issue degree: The major concept in superscalar processing is how many instructions we can issue per cycle. If we issue k number of instructions per cycle in a superscalar processor, in that case the processor is called a k-degree superscalar processor. If we want to exploit the full parallelism from a superscalar processor then k instructions must be implement in parallel.

For example, we consider a 2-degree superscalar processor with 4 pipeline phases for instruction cycle, i.e. decode instruction (DI), instruction fetch (IF), fetch the operands (FO), execute the instruction (EI) as shown below in Figure. In this superscalar processor, two instructions are issued per cycle as shown below in Figure. Here, 6 instructions in 4 stage pipelines have been implemented in 6 clock cycles. Under ideal conditions, after steady state, two instructions are being implemented per cycle.

                                                 20_Instruction issue degree.png

                     Superscalar Processing of instruction cycle in 4-stage instruction pipeline

For executing superscalar processing, some important hardware must be provided which is discussed below:

  • The necessity of data path is increased with the degree of superscalar processing. Assume, one instruction size is 32 bit and we are using 2-degree superscalar processor, then 64 data path by the instruction memory is required and 2 instruction registers are also required.
  • Multiple implementation units are also required for implementing multiple instructions and to avoid resource conflicts.

Data dependency will be increased in superscalar processing if sufficient hardware is not given. The added hardware provided is known as hardware machine parallelism. Hardware parallelism makes sure that resource is available in hardware to exploit parallelism. Another alternative is to exploit the instruction level parallelism inherent in the code. This is achieved by transforming the source code by an optimizing compiler like that it reduces the dependency and resource conflicts in the resulting code.

Many popular commercial processors have been executed with superscalar architecture like IBM RS/6000, MIPS R4000, DEC 21064, Power PC, Pentium, etc.


Related Discussions:- Instruction issue degree

Design a mod-12 synchronous up counter, Design a mod-12 Synchronous up coun...

Design a mod-12 Synchronous up counter. Ans. Design of a mod 12 synchronous counter by using D-flipflops. I state table Present state                                   Next

What are disadvantages of eprom, What are disadvantages of EPROM? The c...

What are disadvantages of EPROM? The chip must be physically removed from the circuit for reprogramming and its whole contents are erased by the UV light.

Message passing model, In the message-passing model, there exists a set of ...

In the message-passing model, there exists a set of tasks that use their own local memories during computation. Multiple tasks can reside on the similar physical machine as well ac

What is the difference among a canvas and a scroll panel, Canvas is a compo...

Canvas is a component. ScrollPanel is a container. Canvas is a rectangular area where the application can draw or trap input events. ScrollPane executes horizontal and vertical scr

Illustrate the ftp commands, Q. Illustrate the FTP commands? FTP includ...

Q. Illustrate the FTP commands? FTP includes many commands however only few are used to retrieve a file. A user is required to understand the three basic commands to connect to

Determine the gray code for decimal number, Determine the equivalent Gr...

Determine the equivalent Gray code for decimal number 6 ? Ans. The equivalent Gray code for decimal number 6 is 0101 Because the Decimal number 6 is equivalent to binary nu

What is ai checkers, The major programs here are Arthur Samuel's, the rote ...

The major programs here are Arthur Samuel's, the rote learning method which is a lot like a memory based method, generalization learning which is a lot like backprop and a signatur

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