What is a difference between RISC and CISC
What is a difference between RISC and CISC
Did you try to find something useful with google (keywords: “risc cisc comparison”)? You will get a lot of information about this topic.
RISC : A reduced Instruction Set computer
CISC : A Complex Instruction Set Computer
I found a great site with a lot of info about CISC and RISC.
But from the questions asked at EDAboard it doesn't semms that many EDAboard members have heard of of it yet.
It's a web site called Google: www.google.com
Please try this link, there's a lot of info about CISC and RISC.
Maybe we should add this link as an annoucement at the top of the forum.
They even have info of almost all other topics too.
If it still doesn't help you, theres something called an encyclopedia.
Try to look up CISC and RISC in an encyclopedia:
You can even look up other strange microcontroller words such as ARM, AVR, PIC, MIPS, PowerPC, Compiler, Assembler etc. etc.
i think that's a terrific idea!
RISC has less instructions but more hardware
CISC has less hardware but more instructions
Well, simply this is no true.
As name says (Reduced Instruction Set Computer) RISC has less instructions ussualy with only one clock cycle .
Whith less instructions you don't need complex instruction decoder, so RISC cores need less transistors (chip area), less power (excelent for mobile units) and higher core speeds than CISCs for same technology.
First RISC architectures were developed for SPACE programs and GaAs technologies (only 40K transistors per chip). For these technologies RISC is only one solution.
Main benefit of RISC architecture is high level language programing.
There is very small defference between programs written in C and programs written in pure assembler.
RISC is low power, high-speed, compiler and programer friendly high level languages oriented architecture.
If you need complex instruction (operation) with RISCs you can synthesize this instructions in software with avaliable RISC instructions.
RISC architectire is not good in all cases especially if your application frequently needs some complex instructions which are not implemented with RISC instruction set.
With CISC architecture you don't always need all complex instruction for some simple tasks. So in most cases you don't use efficient avaliable chip area and waste chip power.
For space and mobile products RISC is only one solution for other products you can use CISC or RISC architectures.
RISC generally donot implements accumulator, yuo have to work with registers. RISC instructions executes in one clock cycle. For that pipelining concept is used. In RISC number of instructions are less.
RISC architecture was invoked by the students of berkeley under the tutelage' of professors Hennessy and Patterson and you can also find a book penned by these two authors.They have explained all the architectural concepts in terms if RISC instructions.The difference between RISC ad CISC is the number of instructions involved which has direct relation with the number of transistors packed inside.for instance even multiplication is written as continuous additions in RISC rather it is a one step process in the case of CISC.This again deals with the delay involved and also with the power dissipation.
Hope this helps
risc is REDUCED INSTRUCTION SET COMPUTER...
it has only few fixed instructions like addition substation etc...
where as cisc have large no of instructions...like multiply divivde etc...
if we want to multiply in cisc we have to do it using basic equation like adding and shifting...
main advantage of risc is its reduced complexity....
Ri sc : data memory and prog memory is separate , instruction set is orthogonal.
Cise : data memory and prog memory is same , instruction set is not orthogonal.
Bacisally pc/microprocessor is cise and microcontroller is rise.
basically the in CISC there is common data and address bus is used to fetch the data from code and data memory
but in the RISC controllers in which the different buses used for the code and data memory
= von Neuman Architecture, ie Pentium, Motorola 68 series, Renesas M16 series, Renesas H8 seriescommon data and address bus is used to fetch the data from code and data memory
= Havard Architecture, ie 8051(CISC), AVR (RISC), PIC (RISC)the different buses used for the code and data memory
That is not the difference between CISC and RISC!
we now know the difference between risc and cisc ,
but what is the common between them????
the first common thing is that both are computing machines
they are made using different hardware architecture
and both of them had their own qualities
now the machine developers are trying to develop systems which had the qualities of both RISC and CISC and reduce the limitations.