How does the computer execute a program, Computer Engineering

Assignment Help:

Let's attempt to answer a fundamental question: 'How does the Computer execute a Program?' Let's describe this with the help of an example from higher level language domain.

Problem:  Write a program to add two numbers.

A sample C program (Assuming two fixed values of numbers as a = 5 and b = 2)

1.  #include < stdio.h >

2. main ()

3.    {

4.  int a =5, b=2, c;

5. c= a+b;

6. printf ("\n The added value is: % d", c);   

7.           }

Program at line 4 states variables which will be equal to 3 memory locations that are a, b and c.  At line 5 these variables are added along with at line 6 value of c is printed.

However how will these instructions be executed by CPU? First you have to compile this program to convert it to machine language. Though how will the machine instructions look like? Let's suppose a hypothetical instruction set of machines of a size of 16 binary digits (bits) data and instructions. Each one of the instruction of machine comprises two components: (a) Operation code which specifies the operation which is to be performed by instruction and (b) Address of operand in memory on that given operation is to be performed.

Let's further presume that size of operation code is supposed to be of six bits consequently rest 10 bits are for address of operand. Also the memory word size is presumed to be of 16 bits. Figure below shows instruction and data formats for this machine.  To simplify our discussion let's present operation code employing Mnemonics such as ADD, LOAD, STORE and signed decimal values for data and decimal values of operand addresses. 

756_How does the Computer execute a Program.png


Related Discussions:- How does the computer execute a program

Why are interrupt masks provided in any processor, Why are interrupt masks ...

Why are interrupt masks provided in any processor? Interrupt mask enable the higher priority devices comes first and there for lower priority devices comes last. The interrupt

What is the use of urgent pointer in tcp segment, What is the use of urgent...

What is the use of urgent pointer in TCP segment? For accommodation out of band signaling, TCP permits the sender to identify data as urgent, implies that the receiving program

Compare putchar function with the getchar function, Normal 0 fa...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

What is control function, Q. What is control function? If transfer is t...

Q. What is control function? If transfer is to take place only under a predetermined control condition then this condition can be specified as a control function. For illustrat

What is trivial file transfer protocol, What is trivial file transfer proto...

What is trivial file transfer protocol? Explain briefly? Trivial File Transfer Protocol (i.e. TFTP) is helpful for bootstrapping a hardware device which does not have a disk on

What is interrupt vector table, Interrupt vector table is always created in...

Interrupt vector table is always created in first 1K area of the memory. Explain why? When CPU receives an interrupt type number from PIC, it uses this number to look up corres

Pre-os and runtime sub-os functionality, In a raw Itanium, a "Processor Abs...

In a raw Itanium, a "Processor Abstraction Layer" (PAL) is integrated into the system. When it is booted the PAL is loaded into the CPU and gives a low-level interface that abstrac

What do you meant by an expert system, (a) What do you meant by an Expert S...

(a) What do you meant by an Expert System (ES) and explain briefly the essential differences between a Decision Support system and ES. (b) What are decision tables and what are

Copy file from a floppy disk to the hard disk, Q. Copy file from a floppy d...

Q. Copy file from a floppy disk to the hard disk? While using a PC, often you need to copy file from a floppy disk to the hard disk or vice-versa.  For instance, you buy some s

Explain about communication displays and matrix, Q. What is communication D...

Q. What is communication Displays and Matrix? Communication Displays Communication displays offer support in concluding frequency of communication whether congestion in me

Write Your Message!

Captcha
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!

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