2-9
OVERVIEW OF THE 80C186 FAMILY ARCHITECTURE
Figure 2-5. Processor Status Word
Register Name:
Processor Status Word
Register Mnemonic:
PSW (FLAGS)
Register Function:
Posts CPU status information.
Bit
Mnemonic
Bit Name
Reset
State
Function
OF
Overflow Flag
0
If OF is set, an arithmetic overflow has occurred.
DF
Direction Flag
0
If DF is set, string instructions are processed high
address to low address. If DF is clear, strings are
processed low address to high address.
IF
Interrupt
Enable Flag
0
If IF is set, the CPU recognizes maskable interrupt
requests. If IF is clear, maskable interrupts are
ignored.
TF
Trap Flag
0
If TF is set, the processor enters single-step mode.
SF
Sign Flag
0
If SF is set, the high-order bit of the result of an
operation is 1, indicating it is negative.
ZF
Zero Flag
0
If ZF is set, the result of an operation is zero.
AF
Auxiliary Flag
0
If AF is set, there has been a carry from the low
nibble to the high or a borrow from the high nibble
to the low nibble of an 8-bit quantity. Used in BCD
operations.
PF
Parity Flag
0
If PF is set, the result of an operation has even
parity.
CF
Carry Flag
0
If CF is set, there has been a carry out of, or a
borrow into, the high-order bit of the result of an
instruction.
NOTE: Reserved register bits are shown with gray shading. Reserved bits must be written to a
logic zero to ensure compatibility with future Intel products.
15
0
O
F
D
F
I
F
T
F
S
F
Z
F
A
F
P
F
C
F
A1035-0A
Содержание 80C186EA
Страница 1: ...80C186EA 80C188EA Microprocessor User s Manual...
Страница 2: ...80C186EA 80C188EA Microprocessor User s Manual 1995...
Страница 19: ......
Страница 20: ...1 Introduction...
Страница 21: ......
Страница 28: ...2 Overview of the 80C186 Family Architecture...
Страница 29: ......
Страница 79: ......
Страница 80: ...3 Bus Interface Unit...
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Страница 129: ......
Страница 130: ...4 Peripheral Control Block...
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Страница 139: ......
Страница 140: ...5 ClockGenerationand Power Management...
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Страница 166: ...6 Chip Select Unit...
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Страница 190: ...7 Refresh Control Unit...
Страница 191: ......
Страница 205: ......
Страница 206: ...8 Interrupt Control Unit...
Страница 207: ......
Страница 239: ...INTERRUPT CONTROL UNIT 8 32...
Страница 240: ...9 Timer Counter Unit...
Страница 241: ......
Страница 265: ......
Страница 266: ...10 Direct Memory Access Unit...
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Страница 295: ...DIRECT MEMORY ACCESS UNIT 10 28...
Страница 296: ...11 Math Coprocessing...
Страница 297: ......
Страница 314: ...12 ONCE Mode...
Страница 315: ......
Страница 318: ...A 80C186 Instruction Set Additions and Extensions...
Страница 319: ......
Страница 330: ...B Input Synchronization...
Страница 331: ......
Страница 334: ...C Instruction Set Descriptions...
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Страница 383: ...INSTRUCTION SET DESCRIPTIONS C 48...
Страница 384: ...D Instruction Set Opcodes and Clock Cycles...
Страница 385: ......
Страница 408: ...Index...
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