Effective Address; Register Direct Mode; Data Register Direct; Address Register Direct - Motorola CPU32 Reference Manual

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3.4 Effective Address
Most instructions specify the location of an operand by a field in the operation
word called an effective address field or an effective address (EA»). An EA is
composed of two 3-bit subfields: mode specification field and register
specification field. Each of the address modes is selected by a particular value
in the mode specification subfield of the EA. The EA field may require further
information to fully specify the operand. This information, called the EA
extension, is in a following word or words and is considered part of the
instruction (see 3.1 Program and Data References).
3.4.1 Register Direct Mode
These EA modes specify that the operand is in one of the 16 multifunction
registers.
3.4.1.1 Data Register Direct
In the data register direct mode, the operand is in the data register specified by
the EA register field.
GENERATION:
ASSEMBLER SYNTAX:
MODE:
REGISTER:
DATA REGISTER:
NUMBER OF EXTENSION WORDS:
EA=Dn
Dn
~o ~
0
~n------~)~I
__________ O_PE_R_AN_D ________
~I
3.4.1.2 Address Register Direct
In the address register direct mode, the operand is in the address register
specified by the EA register field.
GENERATION: EA = An
ASSEMBLER SYNTAX: An
MODE: 001
REGISTER: n 31 0
DATA REGISTER: An
------~)
I OPERAND
I
NUMBER OF EXTENSION WORDS:"
L.. _ _ _ _ _ _ _ _
~~.;;.;,;:.....
_ _ _ _ _ _ _ _
~
3.4.2 Memory Addressing Modes
These EA modes specify the address of the memory operand.
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