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2-19
OVERVIEW OF THE 80C186 FAMILY ARCHITECTURE
Figure 2-11. Flag Storage Format
2.2.1.2 Arithmetic Instructions
The arithmetic instructions (see Table 2-4) operate on four types of numbers:
• Unsigned binary
• Signed binary (integers)
• Unsigned packed decimal
• Unsigned unpacked decimal
A1014-0A
U = Undefined; Value is indeterminate
O = Overflow Flag
D = Direction Flag
I = Interrupt Enable Flag
T = Trap Flag
S = Sign Flag
Z = Zero Flag
A = Auxiliary Carry Flag
P = Parity Flag
C = Carry Flag
Z
6
U
5
A
4
U
3
P
2
U
1
C
0
S
7
T
8
I
9
D
10
O
11
U
12
U
13
U
14
U
15
PUSHF
POPF
LAHF
SAHF
ZUAUPUCS
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