Data Organization and Addressing Capabilities
MOTOROLA
MC68030 USER’S MANUAL
2-13
2.4.8 Address Register Indirect with Index (Base Displacement) Mode
This addressing mode requires an index register indicator and an optional 16- or 32-bit sign-
extended base displacement. The index register indicator includes size and scaling
information. The operand is in memory. The address of the operand is the sum of the
contents of the address register, the scaled contents of the sign-extended index register,
and the base displacement.
In this mode, the address register, the index register, and the displacement are all optional.
If none is specified, the effective address is zero. This mode provides a data register indirect
address when no address register is specified and the index register is a data register (Dn).
31 0
31 0
31 0
31 0
MEMORY ADDRESS:
NUMBER OF EXTENSION WORDS: 1,2, OR 3
EA = (An) + (Xn) + bd
(bd,An,Xn.SIZE*SCALE)
110
n
An
GENERATION:
ASSEMBLER SYNTAX:
MODE:
REGISTER:
ADDRESS REGISTER:
SIGN-EXTENDED VALUE
SIGN-EXTENDED VALUE
SCALE VALUE
OPERAND
+
+
X
BASE DISPLACEMENT:
INDEX REGISTER:
SCALE:
MEMORY ADDRESS
7
0
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