In: Computer Science
convert +38 and +17 to binary using the signed 2s complement representation and enough digits to accomaodate the numbers. Then perform the binary equivalent of (-38) and +17
Calculating 38 in binary: -------------------------- Write down the decimal number and continually divide by 2 to give a result and a remainder. The remainder is either a 1 or a 0. 38 / 2 result 19 remainder 0 19 / 2 result 9 remainder 1 9 / 2 result 4 remainder 1 4 / 2 result 2 remainder 0 2 / 2 result 1 remainder 0 1 / 2 result 0 remainder 1 Read the remainders from bottom to top. ( 38 )10 = ( 100110 )2 So, fill zeros to the front to make it 8 bit ( 38 )10 = ( 00100110 )2 Ones complement = Inverting all the bits in binary = 11011001 Twos complement = Ones complement + 1 = 11011001 + 1 = 11011010 So, -38 in binary is 11011010 ===================================== Calculating 17 in binary: -------------------------- Write down the decimal number and continually divide by 2 to give a result and a remainder. The remainder is either a 1 or a 0. 17 / 2 result 8 remainder 1 8 / 2 result 4 remainder 0 4 / 2 result 2 remainder 0 2 / 2 result 1 remainder 0 1 / 2 result 0 remainder 1 Read the remainders from bottom to top. ( 17 )10 = ( 10001 )2 So, fill zeros to the front to make it 8 bit ( 17 )10 = ( 00010001 )2 So, 17 in binary is 00010001 ===================================== Calculating -38+17 = ------------------------- 11011010 + 00010001 ------------ 11101011 ------------ So, the result of -38+17 in binary is 11101011 we have to convert 11101011 back to decimal to make answer in decimal As MSB is 1, this is in two's complement Ones complement = Twos complement - 1 = 11101011 - 1 = 11101010 Binary = -Inverting all the bits in binary = -00010101 So, The decimal value of 00010101 is 21 So, 11101011 in decimal is -21 Final Answer in binary is 11101011 Final Answer in decimal is -21