User Account

All Pages

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 ?

First generation of computers, THE FIRST GENERATION (1949-1955) ...

THE FIRST GENERATION (1949-1955) The computers in this generation have the following characteristics:     Physically large in size     Inflexible in operations

Memory, why do computer have internal memory as a part of cpu and the inter...

why do computer have internal memory as a part of cpu and the internal bulk memory seprately?

Copmurer, Classify computer systems according to capacity. How they are dif...

Classify computer systems according to capacity. How they are different from computers according to the classification of technology. Provide comparative study also.

Operating system, Ask question describes deadlock avoidance#Minimum 100 wor...

Ask question describes deadlock avoidance#Minimum 100 words accepted#

Memory unit of computer, Memory unit of computer: The Memory  unit is ...

Memory unit of computer: The Memory  unit is an important component of a computer where all the data and information are stored in the form  of binary digits (combination of 0

What is deadlock, explain deadlock procedure.

explain deadlock procedure.

#algorithm, #to determine whether given year is leap year or not

#to determine whether given year is leap year or not

Meaning of primary data, Problem 1 Research designs have a critical and...

Problem 1 Research designs have a critical and directive role to play in the research process. Explain the meaning of research design. Describe the various types of research de

What are the computational factors, Question 1: (a) Initially, human ...

Question 1: (a) Initially, human information processing was believed to occur in 4 distinct stages. State and describe each of those stages. (b) What are the 3 types of

Digital to analogue conversion (dac), Digital to analogue conversion (dac):...

Digital to analogue conversion (dac): Since many systems used on aircraft will require outputs in analogue form, it will be necessary to be able to convert the digital informat

Write Your Message!

Captcha
Order Assignment

Featured Services

Order Now

Popular Subjects

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!

Submit Assignment

Academics

Major Subjects

Majors

Get In Touch

whatsapp: +91-977-207-8620

Phone: +91-977-207-8620

Email: [email protected]

TERMS & POLICIES

HELP & SUPPORT

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