MC68030 Datasheet, PDF (61/602 Pages) Motorola, Inc – ENHANCED 32-BIT MICROPROCESSOR

Data Organization and Addressing Capabilities
Single Effective Address Instruction Format
15
14 13 12 11 10
9
8
7
6
5
0
X
X
X
X
X
X
X
X
X
X
EFFECTIVE ADDRESS
MODE
REGISTER
Brief Format Extension Word
15
14
12 11 10
9
8
7
0
D/A
REGISTER
W/L
SCALE
0
DISPLACEMENT
Full Format Extension Word(s)
15
14
12
11
10
9
8
7
6
5
4
32
0
D/A
REGISTER
W/L
SCALE
1
BS IS
BD SIZE
0
I/IS
BASE DISPLACEMENT (0, 1, OR 2 WORDS)
OUTER DISPLACEMENT (0, 1, OR 2 WORDS)
Field
Definition
Field
Definition
Instruction:
Register General Register Number
Extensions:
Register Index Register Number
D/A
Index Register Type
0 = Dn
1 = An
W/L
Word/Long-Word Index Size
0 = Sign-Extended Word
1 = Long Word
Scale
Scale Factor
00 =1
01 =2
10 = 4
11 = 8
BS
Base Register Suppress:
0 = Base Register Added
1 = Base Register Suppressed
IS
Index Suppress:
0 = Evaluate and Add Index
Operand
1 = Suppress Index Operand
BD SIZE Base Displacement Size:
00 = Reserved
01 = Null Displacement
10 = Word Displacement
11 Long Displacement
I/IS Index/Indirect Selection
Indirect and Indexing Operand
Determined in Conjunction with
Bit 6, Index Suppress
Figure 2-4. Effective Address Specification Formats
Effective address modes are grouped according to the use of the mode. They can be
classified as follows:
Data
A data addressing effective address mode is one that refers to data operands.
Memory A memory addressing effective address mode is one that refers to memory
operands.
Alterable An alterable addressing effective address mode is one that refers to alterable
(writable) operands.
Control A control addressing effective address mode is one that refers to memory
operands without an associated size.
MOTOROLA
MC68030 USER’S MANUAL
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