Bit manipulation techniques, Computer Engineering

Assignment Help:

  We can also use the logical operators to numbers directly and  perform simple bit manipulation . The operators are

    &  Bitwise AND
    |  Bitwise OR
    ^  Bitwise exclusive or 
    ~  Bitwise one's complement i.e. NOT
    <<  Left shift
    >>   Right shift

Example
  A 8 bit number represents a coded function, bit  3-4 describes the operation to be performed on the number in bits 0- 2 and 5-7  the function i.e. 
 
    00    Add
    01    Subtract
    10     Divide
    11    Multiply
 
  Write a Program to extract the number and operation

Answer
We need to extract the bits 3-4, the answer is bit operators 
 
    Assume number is in the variable A i.e.  11011011
 
    Mask off the first number i.e. bit 0-2
    num1 = a & 0x07;        11011011 and
                00000111
                00000011
    
    Mask off the second number i.e. bit 5 -7
    num2 = a & 0xe0;        11011011 and
                11100000
                11000000
 
    We need to shift num2 down by 5 places i.e.
    num2 = num2 >>5;
                00000110

This could be done in one instruction i.e.
    num2 = (a & 0xe0) >> 5;
 
  Mask off the operation bits i.e. bit 4-5
    operation = (a & 0x18) >> 3;
 
  We can then use the switch statement to select each operation
  switch(operation)
  {
  case 0:  
    total = num1+num2;
    break;
  case 1: 
     total = num1-num2;
    break;
  case 2:  
    total = num1/num2;
    break;
  case 3:  
    total = num1*num2;
    break;
  }
Hence the entire program is 
  #include
  void main()
  { 
  char prompt;
  /*Author : Mr James Mc Carren 
  Company: Staffordshire University 
   Date: 26th August 2012 
  Version 1.0 
   Function : To show bit manipulation
   Modifications:   none*/
  int num1,num2,operation,total,a;
  printf("Please enter in the number\n\r");
  scanf("%x",&a);
  num1 = a & 0x07;  
  num2 = (a & 0xe0) >> 5 ;
  operation = (a & 0x18) >> 3;
  switch(operation)
  {
  case 0:   total = num1+num2;
    break;
  case 1:  total = num1-num2;
    break;
  case 2:  total = num1/num2;
    break;
  case 3:  total = num1*num2;
    break;
  }
  printf("The total is %d\n\r",total); 
  printf("Press and key to exit \n\r");
  scanf("\n%c",&prompt);
  }


Related Discussions:- Bit manipulation techniques

Differentiate between motion and shape tween, Question: 1. In Flash, w...

Question: 1. In Flash, what is the purpose of a motion guide layer? 2. Differentiate between Motion and Shape tween. 3. Give the steps to create a layer mask in flash.

Computer architecture, what is complex instruction set computer and reduce...

what is complex instruction set computer and reduced complex instruction set computer

Set up the minunit test framework - mortgage code, Set up the minunit test ...

Set up the minunit test framework examples in your environment (i.e. build or compile the code). Once you can run the example, use the minunit test framework to create and run a bo

Describe types of complements, Q. Describe types of complements? There ...

Q. Describe types of complements? There are two kinds of complements for a number of base (also known as radix) r. These are known as r's complement and (r- 1)'s complement. Fo

Determine a program that is in execution, Determine a program that is in ex...

Determine a program that is in execution is known as Program in execution is known as Process

Define the do while loop, The do while Loop This is very similar to the...

The do while Loop This is very similar to the while loop except that the test occurs at the end of the loop body. This guarantees that the loop is executed at least once before

Why is green screen more popular for compositing, Question: (a) Explain...

Question: (a) Explain clearly, from pre-production to post production how you would carry out the scene with multi-camera. (b) What are the there main aspects that should be

Define external variable declaration, Summarize the distinction between an ...

Summarize the distinction between an external variable definition and an external variable declaration. When we have ''declared'' a variable, we have meant that we have told th

State the implementation of a security policy, State the implementation of ...

State the implementation of a security policy The implementation of a security policy should invariably cover all parameters of security such as physical access to the server,

Performance of caches - computer architecture, Performance of caches: ...

Performance of caches:       Amdahl's Law regarding overall speed up:                  Alternatively, CPU stall can be considered:

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