Most people know that computer stores data in bit pattern using 1s and 0s. But how can computer do this? We'll look at integer first Fixed Point Representation Sign-and-magnitude representation The left most bit represents the sign of number ("0" stands for "+" while "1" stands for "-") The remaining bit represent the binary equivalent of the magnitude of the number 2's complement representation Algorithm: Convert the denary number to binary code If it is +ve, you are finished, else conduct 3 & 4 Changing all 0s to 1s and all 1s to 0s Add 1 to the result binary code. Excess code representation Algorithm (take 128 excess code as example): Add 128 to the denary integer Convert the result value to binary We can use use the above method to represent number with decimals. We, however, seldom use fixed point representation. We use floating point representation instead. Floating Point Representation Floating Point Bit Pattern Divides in several parts Sign of mantissa ("1" = "-", "0" = "+") Magnitude of mantissa Exponent (can be represented by sign-snd-magnitude, 2's complement or excess code) The sign of the number = Sign of mantissa The value of the number = Magnitude of mantissa * 2 exponent Proceed to : Machine Instruction