Fast search of some nibbles in two ints at same offset (C, microoptimisation)

Question

My task is to check (>trillions checks), does two int contain any of predefined pairs of nibbles (first pair 0x2 0x7; second 0xd 0x8). For example:

bit offset:           


        

Answer 1

You could possibly throw out some non-matching candidates earlier:

int nibble_check (uint32_t A, uint32_t B) 
{
    if ( !(A & B & 0x22222222) && !(A & B & 0x88888888))
       return 0;
    //rest of checking here...
}