Motorola MC68030 User Manual

Data Organization and Addressing Capabilities
2-16 MC68030 USER’S MANUAL MOTOROLA
2.4.11 Program Counter Indirect with Displacement Mode
In this mode, the operand is in memory. The address of the operand is the sum of the
address in the PC and the sign-extended 16-bit displacement integer in the extension word.
The value in the PC is the address of the extension word. The reference is a program space
reference and is only allowed for reads (refer to 4.2 Address Space Types ).
2.4.12 Program Counter Indirect with Index (8-Bit Displacement) Mode
This mode is similar to the address register indirect with index (8-bit displacement) mode
described in 2.4.7 Address Register Indirect with Index (8-Bit Displacement) Mode , but
the PC is used as the base register. The operand is in memory. The address of the operand
is the sum of the address in the PC, the sign-extended displacement integer in the lower
eight bits of the extension word, and the sized, scaled, and sign-extended index operand.
The value in the PC is the address of the extension word. This reference is a program space
reference and is only allowed for reads. The user must include the displacement, the PC,
and the index register when specifying this addressing mode.
31 0
31 0
EA = (PC) + d
d ,PC)
111
010
GENERATION:
ASSEMBLER SYNTAX:
MODE:
REGISTER:
PROGRAM COUNTER:
MEMORY ADDRESS:
NUMBER OF EXTENSION WORDS: 1
OPERAND
+
SIGN EXTENDED
031
15
16
16
ADDRESS OF EXTENSION WORD
DISPLACEMENT: INTEGER
31 0
31 0
31 0
31 0
EA = (PC) + (Xn) + d
(d , PC,Xn. SIZE*SCALE)
111
011
+
OPERANDMEMORY ADDRESS:
NUMBER OF EXTENSION WORDS:
GENERATION:
ASSEMBLER SYNTAX:
MODE:
REGISTER:
PROGRAM COUNTER:
INTEGER
SIGN-EXTENDED VALUE
SCALE VALUE + X
DISPLACEMENT:
INDEX REGISTER
SCALE:
1
ADDRESS OF EXTENSION WORD
SIGN EXTENDED
7
8
8
70

Motorola MC68030 Specifications

General

Brand	Motorola
Model	MC68030
Category	Computer Hardware
Language	English