ZiLOG Z80 Handbook page 288

Decimal to Hexadecimal Conversion
1199io =
* * 4
4 A F H Steps in Conversion:
1. Divide decimal # by 16.
2. Save remainder.
3. Repeat until quotient = 0.
4. Remainders in reverse order
represent hexadecimal
equivalent.
0
16) 4 REMAINDER 4-
16 T4 REMAINDER 10-
16) 1199
112
79
64
15 REMAINDER 15-
Hexadecimal Addition and Subtraction
0 1 2 3
4 5 6
OPERAND 2
7 8 9
A B C D
E
F
0 0 1 2 3
4 5 6 7 8 9 A B C D
E F
1
1
2 3 4 5 6
7
8
9 A
B C D E F 10
2 2 3
4
5
6 7 8 9
A B C D E F 10 11
3 3 4 5 6 7 8
9 A B C
D E F 10 11 12
4 4 5 6 7 8
9 A B C D
E
F
10 11 12 13
5
5
6 7 8 9
A B C D E F 10 11 12
13
14
OPERAND 6 6
7
8
9 A B C D
E
F
10 11 12 13 14
15
1 7 7 8 9 A B C
D E F 10 11 12
13 14 15 16
8
8
9 A B C D
E
F
10 11
12 13 14 15 16 17
9
9
A B C D E F 10 11
12 13 14 15 16
17 18
A
A
B
C
D E F 10 11
12 13 14 15 16 17 18
19
B B C D E F
10
11
12 13
14 15 16 17 18 19
1A
C C D
E
F
10
11
12 13 14 15 16
17
18
19 1A
1B
D D E F 10 11 12
13 14 15 16 17 18
19 IA lB
1C
E E F 10
11
12 13
14 15 16 17 18 19
1A 16 1C
1D
F F 10 11 12 13
14 15 16
17
18
19
IA
18
IC
1D
lE
To add operand 1 to operand 2 find sum at intersection. If two digits, a carry to high
order is represented.
To subtract operand 1 from operand 2 find difference in operand 2 column . If operand 2
greater than one digit the high-order 1 represents a borrow from next digit.
297