CODEWITHSUNDEEP
c++bit-manipulation
Floose
Floose

Reputation: 535

Storing 0s and 1s in an array in a 32-bit integer and performing bit operation

I have a array of size 32. Each element in the array is a 0 or 1. I want to be able to store them into the bit positions of a 32-bit integer, and perform bit-wise operations on it. How can I do this ?

Also, if I have two arrays of size 32, and I want to do bitwise operations on the elements with the same index all at once, could I do this ?

op_and[31:0] = ip_1[31:0] & ip_2 [31:0];

I am using the gcc compiler.

Upvotes: 1

Views: 445

Answers (1)

DusteD
DusteD

Reputation: 1410

You can use the or operator | and bitshifting ( << and >> ).

uint32_t myInt = 0;
for( int index=0; index < 32; index++ )
{
  myInt |= ( arrayOf32Ints[i] << i );
}

This example assumes that the values of arrayOf32Ints are either 0 or 1 as per your question. If they may contain "any true" or false value, one should ask for that explicitly (some people would tell you to use !! but the standard does not guarantee that true is 1).

The line would then be

myInt |= ( (arrayOf32Ints[i])?1:0) << i );

In the case you want to set individual bits on or off, you can do:

myInt |= (1<<3); //Sets bit 3 true by shifting 1 3 bits up (1 becomes 4), and ANDing it with myInt.
myInt |= 4; // Sets bit 3 by ANDing 4 (The binary form of 4 is 100) with myInt.
myInt ^= (1<<5);; // Turns OFF bit 5 by XORing it with myInt (XOR basically means "Any bits which are not the same in both numbers")
myInt ^= 16; //Sets bit 5 by XORing it with myInt (16 is 10000 in binary)

Upvotes: 2

Related Questions