1REPRESENTING INTEGER DATA

UNSIGNED BINARY ANDBINARY-CODED DECIMAL

BCD: binary-coded decimal

Each decimal digit individually converted to binary Requires 4 bits per digit 8-bit location hold 2 BCD digits 00 to 99

6810 01101000BCD Hexa: 4 bits can hold 16 values, 0 to F A to F not used in BCD

2SIGN-AND-MAGNITUDE REPRESENTATION

Nines Decimal Representation Examples 9s complement 9s compl. Repr. For: 3-digit nb 467?

999467532

4-digit nb 467?9999467

9532

Sign-and-magnitude value 9990?99999990

9 9990 represents the value 9

3Figure 4.6 Addition as a counting process Figure 4.7 Addition with wraparound

Figure 4.8 Addition with modulus crossing

Ones complement

4Add in 1s complement

Overflow

Overflow sign of result sign both operands

Tens complement scale

5Examples

10s complement of 247 is 1000 247 = 75317 is 1000 017 = 983

Sign and magnitude of 777Begins with a 7 ( 5) negative1000 777 = 223The sign-magnitude value is 223

Alternative 10s comp = 9s comp + 1

Twos complement

2s complement = 1s complement+1

Examples of 2s complement