what is instruction set (CPU)?

Question

For any kind of cpu architecture,

-what is instruction set

-what does it fo

-does it differ from x86 to x64 bit architecture

Answer 1

The processor works by fetching and executing machine codes assembled together as an instruction set. These are essentialy switching instructions in digital format. In its most basic form this will look like a series of ones and zeros. Since it is difficult to remember a series of zeros and ones generally these are represented as Hexadecimal numbers. Still they are not easdy to remeber. Hence nmemonics is used in the form of assembly language which is used to create the instruction set. Here is an example : http://www.erg.abdn.ac.uk/~gorry/eg2069/assembly.html

MOV r0, #0C ;load base address of string into r0

LOAD: MOV r1,(r0) ;load contents into r1

CALL PRINT ; call a print routine to print the character in r1

INC r0 ;point to next character

JMP LOAD ;load next character

The processor has different parts like the registers, the stack, the counter etc. The instruction set manipulates these parts of the processor by switching actions. 0 is off and 1 is on. The switching action takes place billions of times a second. This is the clock speed of a processor and expressed as so many Giga Bytes per second.

For each processor there is a unique set of op-codes. For x86 and x64 architecture there are unique sets parts of which may be common. For more information read about machine code and assembly language :

http://en.wikipedia.org/wiki/Machine_code

http://en.wikipedia.org/wiki/Assembly_language

http://www.scm.tees.ac.uk/users/u0000408/CSY/68Kexamples.htm

Answer 2

Also called a command set, the basic set of commands, or instructions, that a microprocessor understands.

Instruction Set is the 32-bit(X86) and 64-bit(X64)



32-bit refers to the number of bits (the smallest unit of information on a machine) that can be processed or transmitted in parallel, or the number of bits used for single element in a data format. The term when used in conjunction with a microprocessor indicates the width of the registers; a special high-speed storage area within the CPU. A 32-bit microprocessor can process data and memory addresses that are represented by 32 bits.



64-bit therefore refers to a processor with registers that store 64-bit numbers. A generalization would be to suggest that 64-bit architecture would double the amount of data a CPU can process per clock cycle. Users would note a performance increase because a 64-bit CPU can handle more memory and larger files. One of the most attractive features of 64-bit processors is the amount of memory the system can support. 64-bit architecture will allow systems to address up to 1 terabyte (1000GB) of memory. In today's 32-bit desktop systems, you can have up to 4GB of RAM (provided your motherboard that can handle that much RAM) which is split between the applications and the operating system (OS).

Answer 3

The group of machine language instructions that a computer can follow, which may range from a handful to several hundred. It is a fundamental architectural component of a CPU and is either built into the CPU or into microcode, a layer between the instruction set and the circuitry. The instruction length is generally from one to four bytes long. See CISC, RISC, machine language, microcode and CPU.



Machine code - simple instructions that are executed directly by the CPU

As we should hopefully already know, computers are calculators that can only count from 0 to 1.

We have to give them instructions, so they know what to do.

Machine code allows computers to perform the most basic, but essential tasks. Amongst others, the following instructions are important for all processors:

LDA - Loads the contents of the memory address or integer into the accumulator

ADD - Adds the contents of the memory address or integer to the accumulator

STO - Stores the contents of the accumulator into the addressed location



Assembly code is the easy to read interpretation of machine code, there is a one to one matching, one line of assembly equals one line of machine code:



Instruction set - the range of instructions that a CPU can execute

There are many different instructions that we can use in machine code, you have already met three (LDA, ADD, STO), but some processors will be capable of understanding many more. The selection of instructions that a machine can understand is called the instruction set.

Apart from some simple instructions common to all processors, instructions differ CPU to CPU, depending on the CPU's purpose and complexity. So yes, there are some different instructions between 64 and 86 bit architecture



you might also try:

https://en.wikipedia.org/wiki/Instruction_set



http://en.wikibooks.org/wiki/A-level_Computing/AQA/Computer_Components,_The_Stored_Program_Concept_and_the_Internet/Machine_Level_Architecture/Machine_code_and_processor_instruction_set

Answer 4

A set of instructions for the CP{U

If you really wanted to know you would have looked it up for yourself