80C186 INSTRUCTION SET ADDITIONS AND EXTENSIONS
A-4
Figure A-2. Variable Access in Nested Procedures
The first ENTER, executed in the Main Program, allocates dynamic storage space for Main, but
no pointers are copied. The only word in the display points to itself because no previous value
exists to return to after LEAVE is executed (see Figure A-3).
Figure A-3. Stack Frame for Main at Level 1
After Main calls Procedure A, ENTER creates a new display for Procedure A. The first word
points to the previous value of BP (BPM). The second word points to the current value of BP
(BPA). BPM contains the base for dynamic storage in Main. All dynamic variables for Main will
be at a fixed offset from this value (see Figure A-4).
Main Program (Lexical Level 1)
Procedure A (Lexical Level 2)
Procedure B (Lexical Level 3)
Procedure C (Lexical Level 3)
Procedure D (Lexical Level 4)
A1001-0A
BP
SP
Dynamic
Storage
Main
Old BP
15
0
BPM
Display Main
*BPM = BP Value for MAIN
a1002 0a pc
A1002-0A
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: ......