Motorola MC68030 User Manual

Data Organization and Addressing Capabilities
2-12 MC68030 USER’S MANUAL MOTOROLA
2.4.6 Address Register Indirect with Displacement Mode
In the address register indirect with displacement mode, the operand is in memory. The
address of the operand is the sum of the address in the address register plus the sign-
extended 16-bit displacement integer in the extension word. Displacements are always sign-
extended to 32 bits prior to being used in effective address calculations.
2.4.7 Address Register Indirect with Index (8-Bit Displacement) Mode
This addressing mode requires one extension word that contains the index register indicator
and an 8-bit displacement. The index register indicator includes size and scale information.
In this mode, the operand is in memory. The address of the operand is the sum of the
contents of the address register, the sign-extended displacement value in the low-order
eight bits of the extension word, and the sign-extended contents of the index register
(possibly scaled). The user must specify the displacement, the address register, and the
index register in this mode.
31 0
31 0
EA = (An) + d
(d ,An)
101
n
An
GENERATION:
ASSEMBLER SYNTAX:
MODE:
REGISTER:
ADDRESS REGISTER:
MEMORY ADDRESS:
NUMBER OF EXTENSION WORDS: 1
OPERAND
+
SIGN EXTENDED INTEGER
031
15
16
16
MEMORY ADDRESS
DISPLACEMENT:
31 0
31 0
31 0
MEMORY ADDRESS
OPERAND
MEMORY ADDRESS:
NUMBER OF EXTENSION WORDS:
EA = (An) + (XN) + d
(d ,An,Xn.SIZE*SCALE)
110
n
An
GENERATION:
ASSEMBLER SYNTAX:
MODE:
REGISTER:
ADDRESS REGISTER:
INTEGER
SIGN-EXTENDED VALUE
SCALE VALUE
+
0
0
+
X
31
DISPLACEMENT:
INDEX REGISTER
SCALE:
1
7
0
7
SIGN EXTENDED
8
8
31

Motorola MC68030 Specifications

General

Brand	Motorola
Model	MC68030
Category	Computer Hardware
Language	English