define CISC and RISC ?, Basic Computer Science

Assignment Help:
Two competing architectures were developed for improving the architecture of the central processing unit, and different processors are conventional to each one. Both had their power and weaknesses, and as such also had supporters and detractors.
CISC: Complex Instruction Set Computers
Earlier developments were based in the order of the idea that making the CPU more complex and supporting a superior number of potential instructions would lead to amplified performance. This thought is at the root of CISC processors, such as the Intel x 86 ranges, which have very large instruction sets reaching up to and on top of three hundred separate instructions. They also have amplified complexity in other areas, with many more specialized addressing modes and registers also being implemented and variable length of the instruction codes themselves.
Performance was getting better here by allowing the generalization of program compilers, as the range of more advanced instructions available led to fewer refinements having to be made at the compilation process. But, the complexity of the processor hardware and architecture that resulted can cause such chips to be hard to understand and program for, and also means they can be exclusive to produce.
RISC: (Reduced Instruction Set Computers)
In conflict to CISC, the mid-1980s saw the beginnings of the RISC philosophy. The plan here was that the best way to get better performance would be to make simpler the processor workings as much as probable. RISC processors, for example the IBM PowerPC processor, have a greatly simplified and concentrated instruction set, numbering in the region of one hundred instructions or less. Addressing modes are basic back to four or less, and the length of the codes is fixed so as to allow standardization across the instruction set.
Changing the architecture to this extent means that fewer transistors are used to create the processors. This means that RISC chips are much cheaper to produce than their CISC counterparts. As well the reduced instruction set means that the processor can execute the instructions more rapidly, potentially allowing for greater speeds. However, only allowing such easy instructions means a greater burden is placed upon the software itself. Less instructions in the instruction set means a greater stress on the efficient writing of software with the instructions that are accessible. Supporters of the CISC architecture will point out that their processors are of good sufficient performance and cost to make such efforts not worth the problem.
CISC RISC
Large (100 to 300) Instruction Set Small (100 or less)
Complex (8 to 20) Addressing Modes Simple (4 or less)
Specialized Instruction Format Simple
Variable Code Lengths Fixed
Variable Execution Cycles Standard for most
Higher Cost / CPU Complexity Lower
Compilation Simplifies Processor design
Processor design Complicates Software

Related Discussions:- define CISC and RISC ?

How Round robin scheduling algorithm is useful than others ?, Round robin (...

Round robin (RR) is one of the simplest, oldest, fairest and most extensively used algorithms. • In the round robin scheduling, processes are posted in a FIFO manner but are given

RMO CSMS marketing subsystem, I need to write a narrative n overview of the...

I need to write a narrative n overview of the diagram and an analysis of the actors

What are the goals of wap architecture, Question 1 Explain the naming conv...

Question 1 Explain the naming conventions of functions in WML scripts and also explain characteristics of functions in WML Question 2 What is WML input field? Explain WML

Concept of operating system, Concept of operating system: An operating...

Concept of operating system: An operating system is an essential software component of a computer system. The basic  objectives of an operating system are to make the computer

Data processing, Data Processing In any computer-based system, d...

Data Processing In any computer-based system, data storage and retrieval plays an important role. Data storage involves decision about the encoding of data, assignment o

C, Byteland county is very famous for luminous jewels. Luminous jewels are ...

Byteland county is very famous for luminous jewels. Luminous jewels are used in making beautiful necklaces. A necklace consists of various luminous jewels of particular colour. Nec

Properties of Dictionary Keys, Dictionary values encompass no limitations. ...

Dictionary values encompass no limitations. They can be any random Python object, moreover standard objects or user-defined objects. Though, same is not true for the keys. There ar

Software evolution, SOFTWARE EVOLUTION:  As you know that in a compute...

SOFTWARE EVOLUTION:  As you know that in a computer system both hardware and software complement each other  -  one is of hardly any use without the other. Hence, since the ve

Finite Automata, (S**)*=S*** is this set bigger than S*??

(S**)*=S*** is this set bigger than S*??

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