Question

Explain the following in your own words please!

Differentiate between RISC, CISC, and other traditional architectures.

Identify the components of the CPU and elaborate on each.

Explain the use of buses in computers in a paragraph.

Answer 1

Differentiate between RISC, CISC

Answer:

RISC:

A reduced instruction set computer (RISC) is a computer that uses a central processing unit (CPU) that implements the processor design principle of simplified instructions. To date, RISC is the most efficient CPU architecture technology.

This architecture is an evolution and alternative to complex instruction set computing (CISC). With RISC, the basic concept is to have simple instructions that do less but execute very quickly to provide better performance.

->RISC processors have simple instructions taking about one clock cycle. The average clock cycle per instruction (CPI) is 1.5

->Performance is optimized with more focus on software

->It has no memory unit and uses a separate hardware to implement instructions.

->The instruction set is reduced i.e. it has only a few instructions in the instruction set. Many of these instructions are very primitive

->The calculations are faster and precise

->Decoding of instructions is simple

->Execution time is very less

->Used in high end applications such as video processing, telecommunications and image processing

->Hardwired without control memory.

->

• CISC instructions utilize more cycles than RISC
• CISC has way more complex instructions than RISC
• CISC typically has fewer instructions than RISC
• CISC implementations tend to be slower than RISC implementations
• Computers typically use CISC while tablets, smartphones and other devices use RISC

Addressing modes are simplified back to four or less, and the length of the codes is fixed in order to allow standardization across the instruction set.

->Instruction pipelining can be implemented easily.

->Only LOAD/STORE instructions can access memory.

->Mainly used for real time applications.

-> RISC systems shorten execution time by reducing the clock
cycles per instruction (i.e. simple instructions take less time
to interpret).
CISC:

The term CISC stands for ‘’Complex Instruction Set Computer’’. It is a CPU design plan based on single commands, which are skilled in executing multi-step operations.

CISC computers have small programs. It has a huge number of compound instructions, which takes a long time to perform. Here, a single set of instruction is protected in several steps; each instruction set has additional than 300 separate instructions. Maximum instructions are finished in two to ten machine cycles. In CISC, instruction pipelining is not easily implemented.

->CSIC processor has complex instructions that take up multiple clocks for execution. The average clock cycle per instruction (CPI) is in the range of 2 and 15

->Performance is optimized with more focus on hardware.

->It has a memory unit to implement complex instructions.

-> It has a microprogramming unit.

->The instruction set has a variety of different instructions that can be used for complex operations

->CISC has many different addressing modes and can thus be used to represent higher-level programming language statements more efficiently.

->Variable formats (16-64 bits per instruction).

->Used in low end applications such as security systems, home automations, etc.

->Very large instruction sets reaching up to and above three hundred seperate instructions.

->Performance was improved by allowing the simplification of program compilers, as the range of more advanced instructions available led to less refinements having to be made at the compilation process. However, the complexity of the processor hardware and architecture that resulted can cause such chips to be difficult to understand and program for, and also means they can be expensive to produce.

->More specialized addressing modes and registers also being implemented, with variable length instruction codes.

-> Instruction pipelining can not be implemented easily.

->Many complex instructions can access memory, such as direct addition between data in two memory locations.

Identify the components of the CPU and elaborate on each.

Answer:

The three components of the CPU are following,

1. Arithmetic Logic Unit
2. Control Unit
3. Registers

Arithmetic Logic Unit (ALU)

There is electronic circuitry in arithmetic logic unit which executes all airthmetic and logical operations.Its function is obvious from its name.It performs arithmetic calculations like as addition, subtraction, multiplication and division as well as comparisons.The unit can compare numbers, letters, or special characters.There can be more than one Arithmetic logic unit in a CPU, and these ALUs can also be used for the purpose of maintaining timers that help run the computer.


Control Unit(CU)

There is circuitry in the control unit which uses electrical signals to instruct the whole computer system for carrying out or executing,already stored program instructions.Its name clearly shows that it controls and co-ordinates computer components.It extracts instructions from memory and decodes and executes them.In fact it regulates the flow of information through the processor.In short,it can be said ,this component receives, decodes, stores results and manages execution of data that flows through the CPU. Its communication with both arithmetic unit and memory is inevitable.

Registers/The Memory Unit

Registers are temporary storage areas which are responsible for holding the data that is to be processed.They store the instructions and data in a processor.This data is further used by Control Unit.There are some registers that are set aside for specific tasks, these generally include a program counter, stack, and flags.

Answer:

a bus (a contraction of the Latin omnibus) is a communication system that transfers data between components inside a computer, or between computers. This expression covers all related hardware components (wire, optical fiber, etc.) and software, including communication protocols

Versatility: – New devices can be added easily – Peripherals can be moved between computer systems that use the same bus standard ? Low Cost: – A single set of wires is shared in multiple ways ? Manage complexity by partitioning the design