A-5
80C186 INSTRUCTION SET ADDITIONS AND EXTENSIONS
Figure A-4. Stack Frame for Procedure A at Level 2
After Procedure A calls Procedure B, ENTER creates the display for Procedure B. The first word
of the display points to the previous value of BP (BPA). The second word points to the value of
BP for MAIN (BPM). The third word points to the BP for Procedure A (BPA). The last word
points to the current BP (BPB). Procedure B can access variables in Procedure A or Main via the
appropriate BP in the display (see Figure A-5).
After Procedure B calls Procedure C, ENTER creates the display for Procedure C. The first word
of the display points to the previous value of BP (BPB). The second word points to the value of
BP for MAIN (BPM). The third word points to the value of BP for Procedure A (BPA). The
fourth word points to the current BP (BPC). Because Procedure B and Procedure C have the same
lexical nesting level, Procedure C cannot access variables in Procedure B. The only pointer to
Procedure B in the display of Procedure C exists to allow the LEAVE instruction to collapse the
Procedure C stack frame (see Figure A-6).
Old BP
BP
SP
15
0
BPM
BPM
BPM
BPA*
Display A
Dynamic
Storage A
*BPA = BP Value for Procedure A
A1003-0A
Summary of Contents for 80C186EA
Page 1: ...80C186EA 80C188EA Microprocessor User s Manual...
Page 2: ...80C186EA 80C188EA Microprocessor User s Manual 1995...
Page 19: ......
Page 20: ...1 Introduction...
Page 21: ......
Page 28: ...2 Overview of the 80C186 Family Architecture...
Page 29: ......
Page 79: ......
Page 80: ...3 Bus Interface Unit...
Page 81: ......
Page 129: ......
Page 130: ...4 Peripheral Control Block...
Page 131: ......
Page 139: ......
Page 140: ...5 ClockGenerationand Power Management...
Page 141: ......
Page 165: ......
Page 166: ...6 Chip Select Unit...
Page 167: ......
Page 190: ...7 Refresh Control Unit...
Page 191: ......
Page 205: ......
Page 206: ...8 Interrupt Control Unit...
Page 207: ......
Page 239: ...INTERRUPT CONTROL UNIT 8 32...
Page 240: ...9 Timer Counter Unit...
Page 241: ......
Page 265: ......
Page 266: ...10 Direct Memory Access Unit...
Page 267: ......
Page 295: ...DIRECT MEMORY ACCESS UNIT 10 28...
Page 296: ...11 Math Coprocessing...
Page 297: ......
Page 314: ...12 ONCE Mode...
Page 315: ......
Page 318: ...A 80C186 Instruction Set Additions and Extensions...
Page 319: ......
Page 330: ...B Input Synchronization...
Page 331: ......
Page 334: ...C Instruction Set Descriptions...
Page 335: ......
Page 383: ...INSTRUCTION SET DESCRIPTIONS C 48...
Page 384: ...D Instruction Set Opcodes and Clock Cycles...
Page 385: ......
Page 408: ...Index...
Page 409: ......