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3.1 Program and Data References
An M68000 Family processor makes two classes of memory references, each of
which has a complete, separate logical address space.
References to opcodes and extension words are program space references.
Operand reads and writes are primarily data space references. Operand reads
are from data space in all but two cases -
immediate operands embedded in
the instruction stream and operands addressed relative to the current program
counter are program space references. All operand writes are to data space.
3.2 Notation Conventions
EA -
Effective address
An -
Address register n
Example: A3 is address register 3
On -
Data register n
Example: 05 is data register 5
Rn - Any register, data or address
Xn.SIZE*SCALE -
Index register n (data or address),
Index size (W for word, L for long word),
Scale factor (1, 2, 4, or 8 for byte, word, long-word or quad-word scaling)
PC -
Program counter
SR -
Status register
SP -
Stack pointer
CCR -
Condition code register
USP -
User stack pointer
SSP -
Supervisor stack pointer
dn -
Displacement value, n bits wide
bd -
Base displacement
L -
Long-word size
W-Word size
B -
Byte size
(An) -
Identifies an indirect address in a register
MOTOROLA
3-2
DATA ORGANIZATION AND
CPU32 REFERENCE MANUAL
ADDRESSING
CAPABILITIES
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