User's Manual

TABLE OF CONTENTS
Figures
Figure Title Page
1-1 Four Privilege Levels ....... ..... ........... ...... ........ .......... .... .......... .... .......... .................... 1-4
2-1 Segmented Virtual Memory ... ................. ...................... ................. ........... ......... ...... 2-2
2-2 Bytes
and Words in Memory................................................................................... 2-3
2-3 80286/80287 Supported Data Types .......... .................. .............. .......... ........ .......... 2-5
2-4 80286 Base Architecture Register
Set ................................................................... 2-7
2-5
Real Address Mode Segment Selector Interpretation ........................................... 2-9
2-6 Protected Mode Segment
Selector Interpretation ................................................. 2-10
2-7 80286
Stack ............................................................................................................. 2-11
2-8 Stack Operation ....................................................................................................... 2-12
2-9 BP Usage as a Stack Frame Base Pointer ............................................................. 2-13
2-10
Flags Register .......................................................................................................... 2-15
2-11 Two-Component Address ....................................................................................... 2-18
2-12 Use of Memory Segmentation ...................... : ......................................................... 2-20
2-13
Complex Addressing Modes ................................................................................... 2-22
2-14 Memory-Mapped
I/O ................................................................................................ 2-24
2-15 Hierarchy of
Instructions ......................................................................................... 2-27
3-1 PUSH ....................... :............................................................................................... 3-2
3-2 PUSHA...................................................... .................... ........................ ................... 3-3
3-3
POP .......................................................................................................................... 3-4
3-4
POPA ........................................................................................................................ 3-5
3-5 Flag Word Contents .................................. ....................................... ..... ................... 3-6
3-6
SAL and SHL ........................................................................................................... 3-11
3-7 SHR .......................................................................................................................... 3-12
3-8
SAR .......................................................................................................................... 3-12
3-9
ROL .......................................................................................................................... 3-13
3-10
ROR ......................................................................................................................... 3-14
3-11 RCL .......................................................................................................................... 3-15
3-12
RCR .......................................................................................................................... 3-15
3-13 LAHF
and SAHF ...................................................................................................... 3-26
3-14
PUSHF and POPF ................................................................................................... 3-27
4-1 Formal Definition of the ENTER Instruction ........................................................... 4-3
4-2
Variable Access in Nested Procedures .................................................................. 4-4
4-2a
Stack Frame for MAIN at Level 1 ............................................................................ 4-4
4-2b
Stack Frame for Procedure A ........ ...... ...... ................. .................. .......... ................ 4-5
4-2c
Stack Frame for Procedure B at Level 3 Called from A ....... :................................ 4-5
4-2d
Stack Frame for Procedure C at Level 3 Called from B ........................................ 4-6
5-1 a Forming the Segment Base Address .... ........ .............. .......... .............. .................... 5-2
5-1 b Forming the 20-Bit Physical Address in the Real Address Mode .... ........... .......... 5-2
5-2
Overlapping Segments to Save Physical Memory ...... .................. ...... ................... 5-3
5-3
Interrupt Vector Table for Real Address Mode ...................................................... 5-4
5-4
Stack Structure after Interrupt (Real Address Mode) ....................................... :.... 5-5
6-1 Format of the Segment Selector Component ........................................................ 6-2
6-2
Address Spaces and Task Isolation ....................................................................... 6-3
6-3 Segment Descriptor (S = 1) ............ ............ ...... .......... .................. .......... ................. 6-5
6-4
Special Purpose Descriptors or System Segment Descriptors (S=O) ................. 6-6
6-5 LDT Descriptor ........................................................................................................ 6-7
6-6
Virtual-to-Physical Address Translation ...... ...... .......... .............. ............ ................. 6-8
6-7
Segment Descriptor Access Bytes ......................................................................... 6-9
6-8
Memory Management Registers ............................................................................. 6-10
6-9 Descriptor Loading .................................................................................................. 6-11
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