iphone - comparing two numbers, getting the different bits in them and filling up a 16bit register, objective-C -

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this may bit confusing. have 2 numbers, say
x = 56 = 00111000
y = 50 = 00110010
can see there total of 4 different bits between them. need take bits , fill part of 8 bit register. , in same way take 2 numbers ( there 4 bits different in them ) fill remaining part of 8 bit register. know how using objective-c ?

i don't know objective-c, wrote in c , tested it. hope don't mind:

unsigned int diffbits(unsigned int x, unsigned int y) {   unsigned int xor_xy = x^y;   unsigned int result = 0;   unsigned int count = 0;    while (xor_xy)   {     if ( xor_xy & 0x01)     {       result |= ((x & (1 << count)) >> count);       result <<= 1;        result |= ((y & (1 << count)) >> count);       result <<= 1;     }      ++count;     xor_xy >>= 1;   }    // undo last left shift of 'result' in while-loop.   result >>= 1;    return result; }

the logic is: x ^ y (x xor y) - gives bit locations in numbers x , y different. test x bit value of x ^ y , push result. repeat y , push result. right shift x ^ y 1. repeat until x ^ y != 0.


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