Operations on bytes in C#

Question

I'm writing application to control LEDS on LPT. I have everything working except this. This is one small function.

I have sth like that:

I want to build function that will take two argument and return one number: In actual code those binary numers will be in hex. I put them there like that so that it's easier for you to visualize it.

Example1:

arg1 = 1100 1100
arg2 = 1001 0001
retu = 0100 1100

Example2:

arg1 = 1111 1111
arg2 = 0001 0010
retu = 1110 1101

Example3:

arg1 = 1111 0000
arg2 = 0010 0010
retu = 1101 0000

I have no idea how this function should look like. I want it to be as fast as possible.

I'll call this function 200 times per second.

Answer 1

Essentially, the set bits in the second argument are those you want removed. So you can simply and with the negated second argument:

byte Foo(byte a, byte b) {
  return (byte)(a & ~b);
}

Your examples at least follow this.

As Alexandre C. notes in a comment to the question, the function is called an implication, ie A ⇒ B .