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

Keyboard status word generator, Q.  Write short note on Interfacing Keyboar...

Q.  Write short note on Interfacing Keyboard, giving block diagram. Why do we need to introduce circuitry called Keyboard Status Word Generator?

the bias and standard error , A random variable (X) is modelled as an expo...

A random variable (X) is modelled as an exponentially distributed with mean 30 units. Simulate N = 50 samples from this distribution, and every sample must have m = 20 simulated va

Potential of parallelism-parallel computing, Potential of Parallelism P...

Potential of Parallelism Problems in the actual world differ in respect of the degree of natural parallelism inherent in the personal problem domain. Some problems may be simpl

Why disable statements are not allowed in functions, Why disable statements...

Why disable statements are not allowed in functions? If  disble  statement  is used  in function,it  invalids  function  and  its  return  value.  So  disable statements aren't

Define relocatable programs, Relocatable programs? Ans. Relocatable pro...

Relocatable programs? Ans. Relocatable programs can be loaded almost anywhere inside the memory.

Internrt application, what is the significance of telecommunications deregu...

what is the significance of telecommunications deregulation for managers and organization

Determine the simplified sop boolean expression, Reduce the following equat...

Reduce the following equation using k-map Y = BC‾D‾ + A‾BC‾D + ABC‾D + A‾BCD + ABCD Ans. Multiplying the first term with (A+A') Y = A'BC'D' + ABC'D' + A'BC'D + ABC'D + A'BCD + A

Identify which stores most no. of bits in memory store, Which of the memori...

Which of the memories stores the most number of bits ? Ans. 5Mx8 = 5 x 220 x 8 = 40M (max).

Define buffering, Define buffering.  A buffer is a memory area that kee...

Define buffering.  A buffer is a memory area that keeps data while they are transferred among two devices or among a device and an application. Buffering is done for three reas

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