C-3
INSTRUCTION SET DESCRIPTIONS
Table C-3. Flag Bit Functions
Name
Function
AF
Auxiliary Flag:
Set on carry from or borrow to the low order four bits of AL; cleared otherwise.
CF
Carry Flag:
Set on high-order bit carry or borrow; cleared otherwise.
DF
Direction Flag:
Causes string instructions to auto decrement the appropriate index register
when set. Clearing DF causes auto increment.
IF
Interrupt-enable Flag:
When set, maskable interrupts will cause the CPU to transfer control to an
interrupt vector specified location.
OF
Overflow Flag:
Set if the signed result cannot be expressed within the number of bits in the
destination operand; cleared otherwise.
PF
Parity Flag:
Set if low-order 8 bits of result contain an even number of 1 bits; cleared
otherwise.
SF
Sign Flag:
Set equal to high-order bit of result (0 if positive, 1 if negative).
TF
Single Step Flag:
Once set, a single step interrupt occurs after the next instruction executes. TF
is cleared by the single step interrupt.
ZF
Zero Flag:
Set if result is zero; cleared otherwise.
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: ......