Friday, May 27, 2022

CISC vs RISC Architecture | Difference between CISC And RISC Architecture

Hello everyone this is dr diehmann and i welcome you all to this microprocessor and microcontroller tutorial series so in this video we will learn about the differences between sys architecture and risk architecture so what do you understand by this c squared and this risk word okay so first of all we have to understand the meaning then we can .

Directly find out the differences so the full form of cisc is complex instruction set computer this is one architecture where we have complex instruction set okay so we can understand that this instruction said maybe complex one also may be simple one also it consists of some complex instruction architecture or we can say that this contains more .

Number of instruction or large number of instructions it might have more number of addressing modes okay so we will see one by one in the case of risc this is called as the reduced instruction set so this is the reduced instruction set this is the complex in the case of reduced instruction set processor the instruction format will be .

Simpler okay we will see one by one after going through all these 11 differences we will understand what are the differences so the first difference is large number of instructions and addressing modes in this case of syst architecture we have large number of instruction for every type of .

Instruction we will have some micro operations also we can write micro programs also for performing some definite operations okay but in the case of a risk architecture what we can see the has lesser number of instructions and addressing modes we will see in detail in the second difference it is the software-based approach it is the .

Hardware-based approach so this architecture is hardware-based approach why these operations are explained or these are simple in step by step form the memory access is also limited to the store and load operations okay load instructions you can say so these are the hardware based approach the instruction sets are defined inside the .

Rom unit of the processor okay in the third difference micro electronic circuit is activated by micro port to generate a set of control signals here we can activate the micro electronic circuit that the that will have the control signals so to execute an instruction a number of micro operations are performed suppose in the case of cis .

Architecture we have one operation suppose the multiplication we write m ult that is the multiplication and it will contain various operations suppose the address phase resistor effects also have so in the case of risk architecture separate control signals are generated by the control unit of the processor okay we have some .

Control unit inside the processor and that will generate the separate control signals in the case of risk architecture to execute an instruction there is a separate electronic circuitry in the control limit okay this is the third difference the force difference is a micro program is written using micro instructions we can use some .

Micro instructions to define some micro program so new instructions can be introduced by writing micro programs therefore to make the instructions look simpler suppose the multiplexer process is a long process we want to make it simpler so how we can make it simpler the instruction looks simpler but the complexity of the hardware is more okay .

Directly we write mult a comma b then it will multiply the content of the a and b okay but this instruction looks simpler but the performance or the operations unit will handle it is going to be complex one in the case of risk architecture it is a hardwired approach or it is all it is also called as the hardware based approach and micro .

Programming is not used here we do not write here we cannot define some micro program by writing codes here already there is fine set of quotes if the instructions are more then this approach becomes complex we cannot directly define some more micro programs in the case of risk architecture so this was .

The fourth difference so in the fifth difference we have variable length instruction format okay all the instruction format may be of different bit length it may be 16 bit long it may be 32 bit long also it may be 64 bit long also at the same time that within the same micro program or the same operation there might have different bit .

Long instructions okay it is difficult to be managed by the program counter therefore the program does not know therefore the program counter does not know how much long is the instruction format is in this case therefore it becomes complex to be managed by the program holder so what is the program counter we know that the program counter .

Contains the memory of the next instruction to be executed in the case of risk architecture fixed length instruction format it may be of 8 bit long also all the instruction will be up 8 bit long it may be 16 bit long also then all the remaining instructions also defined in the 16 bit format okay it benefits the .

Program counter by knowing where to start start and where to stop okay now go to our let's go to six difference in the sixth difference the architecture is more powerful one more powerful it has more number of instructions to perform various operations we can directly write the instruction suppose we have the division then we directly .

Write the division code okay division upward and the operand and then we can directly execute the operation but here we need some complex hardware to manage this instruction or to manage this micro operations inside the operation okay new instructions can be introduced by writing new microprograms here we have already seen this point okay so we can .

Write new micro instructions to make it is a micro program in the case of risk architecture it is less powerful why this less powerful it has simple instruction set and simple addressing mode this supports lesser number of simple instructions most risk instructions use register to register operations okay in the case of a disk .

Architecture we use ready resistors to store the values and then we perform the operation we do the operations in the register itself but in the case of cisc architecture we perform the operations in the memory unit we will see the later part the seven difference is seventh difference is it is slower six architecture is slower why because its .

Instruction may be of different length first is that that one and second is that it might contain some micro operations or micro instructions or inside the same micro program we define some micro instructions so each instruction may be a complex type therefore it is slower okay in the case of .

Risk architecture it is faster wipes faster because the instructions are simpler and they can be executed within the same clock period and each instruction can be executed within the same cycle of the clock now the eighth difference is the higher post the complex instruction set processor the instruction set is complex one therefore .

Each instruction set we can define some micro operations also the main reason is the micro programming we can write some micro program to execute some micro operations therefore it has higher cost and in the case of risk architecture we have simple instruction set and we have fixed length instruction format therefore it has lower cost in the ninth .

Difference we have the sys architecture has multiple cycle instruction each instruction might need multiple number of cycles or the clock periods to perform the same instruction in one instruction we might need four five six number of clock cycles to perform the operation but single cycle instructions are written in the case of .

Risk architecture in the case of reduced instruction set computer each instruction will be executed within single clock cycle okay and the intent difference is the different calculations are performed in the memory but in the case of a risk architecture what we have registers are used for the various micro operations okay here we use different .

Types of registers to perform the operations memory access is limited to the load and the store instructions only we use the load that is the load one is the instruction and store is that another instruction to access the memory store means we will store some data in the memory and load means we will read some data in the from the memory so .

These are the only two instructions used in the most risk based architecture now we have to know some examples in the case of example we can say here we have intel 486 386 and pentium processors maintain one two three four we have many regenerations of pentium core processors .

Then we have this motorola generations and there are many more okay and in the case of a risk architecture we have this mips arm arm is the most famous one now in the case of mobile architecture also and we have this sun spark okay in most of the super computers in the last year 2020 using the risk based architecture super computers are designed so these .

Are all the differences among the sisk and the risk architecture thank you for watching if you have any question please put it in the comment section below also like share and subscribe to my channel thank you you


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