Motorola M6800 User Manual
Page 24
MPU-24
2
1
2 2
R=1
0
2 1
R=1
102
6
3
2 6
R=0
1
2 3
R=1
1102
0
2 1
R=1
7
3
2 7
R=1
1
2 3
R=1
1112
0
2 1
R=1
therefore 28 = 102, 68 = 1102, & 78 = 1112, and
2678 = 101101112
Digital computers are designed to use binary numbers in their
working registers. The working registers vary in number of bits depending on
the manufacturer. The Motorola M6800 micro-processor utilizes, in general, 8
bit words (or registers). This leads to another number base, not yet
mentioned, of hexadecimal. Hexadecimal is really a base 16 number system and
can be handled in exactly the same manner as base 8 or base 2. In
hexadecimal, four bits (in binary)represents one hexadecimal number. Thus ,
an eight bit register can be represented by a hex number of 2 digits long. To
illustrate, lets assume we have the number of 1478 in an eight bit register.
This in binary form is 01100111 . If this bit pattern is divided into 2-four
bit words of 0110 & 0111, then in hex, 1478 can be represented as 6716. To
prove both are equal, lets convert both back to their base 10 number.