2-27
OVERVIEW OF THE 80C186 FAMILY ARCHITECTURE
2.2.1.6
Processor Control Instructions
Processor control instructions (see Table 2-11) allow programs to control various CPU functions.
Seven of these instructions update flags, four of them are used to synchronize the microprocessor
with external events, and the remaining instruction causes the CPU to do nothing. Except for flag
operations, processor control instructions do not affect the flags.
2.2.2
Addressing Modes
The 80C186 Modular Core family members access instruction operands in several ways. Oper-
ands can be contained either in registers, in the instruction itself, in memory or at I/O ports. Ad-
dresses of memory and I/O port operands can be calculated in many ways. These addressing
modes greatly extend the flexibility and convenience of the instruction set. The following para-
graphs briefly describe register and immediate modes of operand addressing. A detailed descrip-
tion of the memory and I/O addressing modes is also provided.
2.2.2.1
Register and Immediate Operand Addressing Modes
Usually, the fastest, most compact operand addressing forms specify only register operands. This
is because the register operand addresses are encoded in instructions in just a few bits and no bus
cycles are run (the operation occurs within the CPU). Registers can serve as source operands, des-
tination operands, or both.
Table 2-11. Processor Control Instructions
Flag Operations
STC
Set Carry flag
CLC
Clear Carry flag
CMC
Complement Carry flag
STD
Set Direction flag
CLD
Clear Direction flag
STI
Set Interrupt Enable flag
CLI
Clear Interrupt Enable flag
External Synchronization
HLT
Halt until interrupt or reset
WAIT
Wait for TEST pin active
ESC
Escape to external processor
LOCK
Lock bus during next instruction
No Operation
NOP
No operation
Summary of Contents for 80C186XL
Page 1: ...80C186XL 80C188XL Microprocessor User s Manual...
Page 2: ...80C186XL 80C188XL Microprocessor User s Manual 1995...
Page 18: ...1 Introduction...
Page 19: ......
Page 27: ......
Page 28: ...2 Overview of the 80C186 Family Architecture...
Page 29: ......
Page 79: ......
Page 80: ...3 Bus Interface Unit...
Page 81: ......
Page 127: ......
Page 128: ...4 Peripheral Control Block...
Page 129: ......
Page 137: ......
Page 138: ...5 ClockGenerationand Power Management...
Page 139: ......
Page 154: ...6 Chip Select Unit...
Page 155: ......
Page 178: ...7 Refresh Control Unit...
Page 179: ......
Page 193: ......
Page 194: ...8 Interrupt Control Unit...
Page 195: ......
Page 227: ......
Page 228: ...9 Timer Counter Unit...
Page 229: ......
Page 253: ......
Page 254: ...10 Direct Memory Access Unit...
Page 255: ......
Page 283: ......
Page 284: ...11 Math Coprocessing...
Page 285: ......
Page 302: ...12 ONCE Mode...
Page 303: ......
Page 306: ...A 80C186 Instruction Set Additions and Extensions...
Page 307: ......
Page 318: ...B Input Synchronization...
Page 319: ......
Page 322: ...C Instruction Set Descriptions...
Page 323: ......
Page 371: ......
Page 372: ...D Instruction Set Opcodes and Clock Cycles...
Page 373: ......
Page 396: ...Index...
Page 397: ......