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

Synchronous, What are differences between Synchronous, Asynchronous and I s...

What are differences between Synchronous, Asynchronous and I synchronous communication? Sending data encoded in your signal needs that the sender and receiver are both by using

Name the processes of oom, Name the processes of OOM In OOM the modelli...

Name the processes of OOM In OOM the modelling passes through the given processes: System Analysis System Design Object Design, and Final Implementation.

Explain speedup performance and issues in pipelining, Speedup First, we...

Speedup First, we take the speedup factor which is we see how much speed up performance we achieve by pipelining. First we take ideal case for measuring the speedup. Let n b

What is persistence, What is Persistence When you make an object, it e...

What is Persistence When you make an object, it exists for so long as you need it, but under no circumstances object exist when program terminates. While this makes sense at s

Resetting the computer, Sometime you may have to reset your computer (i.e.,...

Sometime you may have to reset your computer (i.e., Reboot DOS) when it is still running because DOS does not work accurately. To reset your computer you have two choices: 1. P

Explain opening files for reading only in c, Opening Files for Reading Only...

Opening Files for Reading Only     : A data file is a file that you can open and read its contents visually - for example, C source files, .dat files, HTML etc - anything that look

Writing down your own interrupt service routines, Q. Writing down your own ...

Q. Writing down your own Interrupt Service Routines? Here are a few rules which should be kept in mind while writing down your own Interrupt Service Routines: 1.  Use Int 21

Program in c, addition c program for token separation

addition c program for token separation

Efficiency of vector processing over scalar processing, Efficiency of Vecto...

Efficiency of Vector Processing over Scalar Processing: We know that, a sequential computer processes scalar operands one at a time. Thus, if we have to process a vector of len

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