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 ?

Tech ed, can you help me convert binary into decimals?

can you help me convert binary into decimals?

Cryptography, Consider the one-time pad encryption scheme to encrypt a 1-bi...

Consider the one-time pad encryption scheme to encrypt a 1-bit message m, and assume m is chosen with uniform distribution from message space M={0,1}. Let E1 be the event "message

Display the item in red colour on a web page, QUESTION (a) Give the app...

QUESTION (a) Give the appropriate syntax to implement a Client-Side Image Map, specifying all possible attributes where required (b) List the benefits of using Cascading Sty

We will compare the performance of a vector processor, In this problem we w...

In this problem we will compare the performance of a vector processor with a system that contains a scalar processor and a GPU-based coprocessor. In the hybrid system, the host pr

Basic, WAP TO ACCEPT MARKS OF THREE SUBJECT FOR STUDENT & CALCULATE TOTAL M...

WAP TO ACCEPT MARKS OF THREE SUBJECT FOR STUDENT & CALCULATE TOTAL MARKS AND PERCENTAGE

Explanation pre increment with example, Problem 1 What is precedence of...

Problem 1 What is precedence of operators? How are expressions evaluated using precedences? Defining precedence of operators Explanation of how expressions are evaluat

COMPUTER ORGANIZATION, Ask questio2. Define interrupt n #Minimum 100 words ...

Ask questio2. Define interrupt n #Minimum 100 words accepted#

CAI, explain CAI pitfalls

explain CAI pitfalls

Data communications and networks, A magazine publisher based in Nairobi has...

A magazine publisher based in Nairobi has branch in Kisumu, and one in Mombasa. The company has kept in touch by telephone and courier service. Each office is networked. The networ

Database management, what is the sql command to List all the join condition...

what is the sql command to List all the join conditions or join paths (pairwise) existing between tables.

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