9/29/95
SECTION 1: OVERVIEW
UM Rev 1
MOTOROLA
M68020 USER’S MANUAL
vii
TABLE OF CONTENTS
Paragraph
Page
Number
Title
Number
Section 1
Introduction
1.1
Features ..................................................................................................1-2
1.2
Programming Model ................................................................................1-4
1.3
Data Types and Addressing Modes Overview ........................................1-8
1.4
Instruction Set Overview .........................................................................1-10
1.5
Virtual Memory and Virtual Machine Concepts .......................................1-10
1.5.1
Virtual Memory ....................................................................................1-10
1.5.2
Virtual Machine ....................................................................................1-12
1.6
Pipelined Architecture .............................................................................1-12
1.7
Cache Memory ........................................................................................1-13
Section 2
Processing States
2.1
Privilege Levels .......................................................................................2-2
2.1.1
Supervisor Privilege Level ...................................................................2-2
2.1.2
User Privilege Level .............................................................................2-3
2.1.3
Changing Privilege Level ..................................................................... 2-3
2.2
Address Space Types .............................................................................2-4
2.3
Exception Processing..............................................................................2-5
2.3.1
Exception Vectors ................................................................................2-5
2.3.2
Exception Stack Frame .......................................................................2-6
Section 3
Signal Description
3.1
Signal Index ............................................................................................3-2
3.2
Function Code Signals (FC2–FC0) .........................................................3-2
3.3
Address Bus (A31–A0, MC68020)(A23–A0, MC68EC020) ....................3-2
3.4
Data Bus (D31–D0) .................................................................................3-2
3.5
Transfer Size Signals (SIZ1, SIZ0) .........................................................3-2
3.6
Asynchronous Bus Control Signals .........................................................3-4
3.7
Interrupt Control Signals..........................................................................3-5
3.8
Bus Arbitration Control Signals ...............................................................3-6
3.9
Bus Exception Control Signals ................................................................3-6
3.10
Emulator Support Signal .........................................................................3-7
3.11
Clock (CLK) .............................................................................................3-7
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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