Intel 80286 User Manual

TABLE OF CONTENTS
Page
Avoiding Underflow and Overflow .......................................................................... 4-16
Final Adjustments ............................ ....... .............. ........... .............. .......................... 4-17
Output Format ................ .............. ............ ....................................... ......... .............. ..... 4-17
Trigonometric Calculation Examples ...... ...... .............. ............ .............. .................. ....... 4-17
FPTAN and FPREM .................................................................................................... 4-17
Cosine Uses Sine Code .............................................................................................. 4-18
APPENDIX A
MACHINE INSTRUCTION ENCODING AND DECODING
APPENDIX B
COMPATIBILITY BETWEEN THE
80287 NPX AND THE 8087
APPENDIX C
IMPLEMENTING THE IEEE
P754 STANDARD
Options Implemented in the 80287 ................................................................................ C-1
Areas of the Standard Implemented in Software ................... C-1
Additional Software to Meet the Standard .... .................. ....... ..... ................... ............... C-2
GLOSSARY OF 80287 AND FLOATING-POINT TERMINOLOGY
INDEX
Figures
Figure Title Page
1-1 Evolution and Performance of Numeric Processors .............................................. 1-1
1-2 '80287 NPX Block Diagram ...................................................................................... 1-7
1-3 80287 Register Set ........................... ....... .............. ..... ...... .............. ......................... 1-9
1-4 80287 Status Word ............ ..... ............... ......... ........ ..... ...... ...... ......... .......... ........ ....... 1-10
1-5 80287 Control Word Format ........ ...... ............ ..... ....... ....... ....................... ............... 1-12
1-6 80287
Tag Word Format .......................................................................................... 1-13
1-7 80287 Instruction
and Data Pointer Image in Memory .......................................... 1-13
1-8 80287 Number System ............................................. , .............................................. 1-15
1-9 Data Formats ............................................................. : .............................................. 1-16
1-10 Projective versus Affine Closure . ..... ................ ........... ....... ......... ....... ........ ............. 1-20
1-11· Arithmetic Example Using Infinity ............................................. : .... ; ......................... 1-37
2-1 FSAVE/FRSTOR Memory Layout ........................................................................... 2-18
2-2 FSTENV/FLDENV Memory Layout ........................ ; .................................... ; ........... 2-19
2-3 Sample 80287 Constants ........................................................................................
2-41
2-4 Status Word RECORD Definition ............................................................................ 2-42
2-5 Structure Definition ..................................................... ; ............. ......................... ; ..... 2-42
2-6 Sample PL/M-286 Program .................................................................................... 2-44
2-7 Sample ASM286 Program ....................................................................................... 2-46
2-8 Instructions
and Register Stack .............................................................................. 2-47
2-9 Synchronizing References to Shared
Data . ..................... ..... ..... ........... ........... ...... 2-50
2-10 Documenting Data Synchronization ........ ......... ......... ...... ...... ......... ........................
2-51
2-11 Nonconcurrent FIST Instruction Code Macro ........................................................ 2-51
2-12 Error Synchronization Examples ............................................................................. 2-52
vii
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Intel 80286 Specifications

General

Processor Type	Microprocessor
Clock Speed	6 MHz to 25 MHz
Transistor Count	134, 000
Addressable Memory	16 MB
Instruction Set	x86
Architecture	x86
Data Bus Width	16-bit
Address Bus Width	24-bit
Operating Modes	Real mode, Protected mode
Process Technology	1.5 µm
Voltage	5V
Introduced	1982
Package	68-pin PGA