Chapter 2 - Bits, data types and operations. In this chapter, we will address the following questions: How do we represent data in a computer? Computer is a binary digital system, what kinds of data do we need to represent? Unsigned integers, unsigned binary arithmetic,. | Chapter 2 Bits, Data Types & Operations Integer Representation Floating-point Representation Logic Operations Data types Our first requirement is to find a way to represent information (data) in a form that is mutually comprehensible by human and machine. Ultimately, we will have to develop schemes for representing all conceivable types of information - language, images, actions, etc. We will start by examining different ways of representing integers, and look for a form that suits the computer. Specifically, the devices that make up a computer are switches that can be on or off, . at high or low voltage. Thus they naturally provide us with two symbols to work with: we can call them on & off, or (more usefully) 0 and 1. 2 - Decimal Numbers “decimal” means that we have ten digits to use in our representation (the symbols 0 through 9) What is 3,546? it is three thousands plus five hundreds plus four tens plus six ones. . 3,546 = + + + How about negative numbers? we use two more symbols to distinguish positive and negative: + and - 2 - Unsigned Binary Integers 3-bits 5-bits 8-bits 0 000 00000 00000000 1 001 00001 00000001 2 010 00010 00000010 3 011 00011 00000011 4 100 00100 00000100 Y = “abc” = + + N = number of bits Range is: 0 i 2 - Signed Magnitude Leading bit is the sign bit -4 10100 -3 10011 -2 10010 -1 10001 -0 10000 +0 00000 +1 00001 +2 00010 +3 00011 +4 00100 Range is: -2N-1 + 1 2 - One’s Complement Invert all bits -4 11011 -3 11100 -2 11101 -1 11110 -0 11111 +0 00000 +1 00001 +2 00010 +3 00011 +4 00100 Range is: -2N-1 + 1 2 - Decimal Numbers “decimal” means that we have ten digits to use in our representation (the symbols 0 through 9) What is 3,546? it is three thousands plus five hundreds plus four tens plus six ones. . 3,546 = + + + How about negative