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 80C186XL
Страница 1: ...80C186XL 80C188XL Microprocessor User s Manual...
Страница 2: ...80C186XL 80C188XL Microprocessor User s Manual 1995...
Страница 18: ...1 Introduction...
Страница 19: ......
Страница 27: ......
Страница 28: ...2 Overview of the 80C186 Family Architecture...
Страница 29: ......
Страница 79: ......
Страница 80: ...3 Bus Interface Unit...
Страница 81: ......
Страница 127: ......
Страница 128: ...4 Peripheral Control Block...
Страница 129: ......
Страница 137: ......
Страница 138: ...5 ClockGenerationand Power Management...
Страница 139: ......
Страница 154: ...6 Chip Select Unit...
Страница 155: ......
Страница 178: ...7 Refresh Control Unit...
Страница 179: ......
Страница 193: ......
Страница 194: ...8 Interrupt Control Unit...
Страница 195: ......
Страница 227: ......
Страница 228: ...9 Timer Counter Unit...
Страница 229: ......
Страница 253: ......
Страница 254: ...10 Direct Memory Access Unit...
Страница 255: ......
Страница 283: ......
Страница 284: ...11 Math Coprocessing...
Страница 285: ......
Страница 302: ...12 ONCE Mode...
Страница 303: ......
Страница 306: ...A 80C186 Instruction Set Additions and Extensions...
Страница 307: ......
Страница 318: ...B Input Synchronization...
Страница 319: ......
Страница 322: ...C Instruction Set Descriptions...
Страница 323: ......
Страница 371: ......
Страница 372: ...D Instruction Set Opcodes and Clock Cycles...
Страница 373: ......
Страница 396: ...Index...
Страница 397: ......