Format - Motorola MC68030 User Manual

15 14 13
X X X
15 14
D/A REGISTER
15 14 12
D/A REGISTER
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
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
Single Effective Address Instruction Format
12 11 10 9
X X X X
Brief Format Extension Word
12 11 10 9
W/L SCALE
Full Format Extension Word(s)
11 10 9
W/L SCALE
BASE DISPLACEMENT (0, 1, OR 2 WORDS)
OUTER DISPLACEMENT (0, 1, OR 2 WORDS)
MC68030 USER'S MANUAL
Data Organization and Addressing Capabilities
8 7 6 5
X X X
8 7
0 DISPLACEMENT
8 7 6 5
1 BS IS BD SIZE
Field
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
EFFECTIVE ADDRESS
MODE REGISTER
4 3 2
0 I/IS
Definition
0
0
0
2-23