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 to avoid race conditions with critical section?, • The key to preventi...

• The key to preventing problem involving shared storage is get some way to prohibit more than one process from reading and writing the shared data concurrently. That part of the p

Synchronizing Threads in python, The threading module offered with Python i...

The threading module offered with Python includes a simple-to-implement locking mechanism that will permit you to synchronize threads. A new lock is formed by calling the Lock() me

Computer graphics, A scaling constant indicates an expansion of length

A scaling constant indicates an expansion of length

Explain with diagram the internal components of alu, Problem 1. Explain...

Problem 1. Explain with diagram the internal components of ALU. Diagram Explaining Internal components 2. What is addressing mode? Explain any five addressing mo

Explain TCP and UDP features in detail and compare, Which applications requ...

Which applications require TCP and why? Also specify which applications require UDP and why? A4) TCP is also known as connection-oriented: setup required between client and server

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

Languages, Languages The language is a program containing rules and...

Languages The language is a program containing rules and guidelines to help us in making programs. There are various languages like C, Basic, COBOL, PASCAL, FORTRAN etc. Th

Stub cables, Stub cables: The stub cables are for bi-directional data m...

Stub cables: The stub cables are for bi-directional data movement between LRU and current mode coupler.  The stub cables also supply power from the LRUs to the current couplers

Mini computers and micro computers, Mini Computers and Micro Computers: ...

Mini Computers and Micro Computers: The mini computers are intermediate in power, and may function as small mainframe computers. They are often dedicated to a particular purpo

General considerations for search - artificial intelligence, General Consid...

General Considerations for Search If we may specify the starting state, the operators and the goal check for a search problem, then we know from where to start, how to move and

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