Intel 80286 User Manual

80286 BASE ARCHITECTURE
BP IS A CONSTANT POINTER TO STACK BASED VARIABLES AND WORK SPACE, ALL REFERENCES
USE BP AND ARE INDEPENDENT OF SP, WHICH MAY VARY DURING A ROUTINE EXECUTION,
PROC N
PUSH AX
PUSH ARRA
LSIZE
CALL PROC_N+1 ----- ..... PROC_N+1:
PUSH BP
PUSH CX
MOV BP, SP
SUB SP, WORK_SPACE
"PROCEDURE
BODY"
MOF BOTTO
S TACK
t
I
1"'--'
I BP
L __ ..I
--
'['
.-
---
MOV SP, BP
POP CX
POP BP
RET
PARAMETERS
RETURN
ADDR
REGISTERS
WORK_SPACE
PARAMETERS
RETURN
ADDR
REGISTERS
WORK_SPACE
r
PROCEDURE N STACK FRAME
PROCEDURE
N+ 1 STACK FRAME
I
DYNAMICALLY ALLOCATED ON
DEMAND RATHER THAN STATICALLY
TOP OF
STACK
STACK SEGMENT BASE
Figure 2-9. BP Usage as a Stack Frame Base Pointer
2-13
G30108
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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