2-11
OVERVIEW OF THE 80C186 FAMILY ARCHITECTURE
Figure 2-7. Currently Addressable Segments
The segment register is automatically selected according to the rules in Table 2-2. All information
in one segment type generally shares the same logical attributes (e.g., code or data). This leads to
programs that are shorter, faster and better structured.
The Bus Interface Unit must obtain the logical address before generating the physical address.
The logical address of a memory location can come from different sources, depending on the type
of reference that is being made (see Table 2-2).
Segment registers always hold the segment base addresses. The Bus Interface Unit determines
which segment register contains the base address according to the type of memory reference
made. However, the programmer can explicitly direct the Bus Interface Unit to use any currently
addressable segment (except for the destination operand of a string instruction). In assembly lan-
guage, this is done by preceding an instruction with a segment override prefix.
B
E
J
B
A
F
D
E
G
H
J
K
CS:
SS:
ES:
FFFFFH
Code:
Stack:
Extra:
DS:
Data:
0H
C
I
H
A1037-0A
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: ......