Motorola M68000 User's Guide Page 100

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86 Assembly Language Programming for the 68000 Family
17. What are the general forms of the address register with index address
ing mode?
18. What restrictions do we have with the PC relative modes?
19. What do you think the instruction MOVE.W 0(PC), DO would do?
20. What is a forward reference?
Answers
1. No, only destination operands are.
2. The ultimate location where the operand data is found. This may be
a register or memory location.
3. Unfortunately no.
4. The register itself.
5. In one or more extension words found with the instruction.
6. 0000000016 to 00007FFFF16 and FFFF800016 to FFFFFFFF16.
7. An value used to represent an address in memory.
8. (An)
9. HOVE.L #$2000,A0
MOVE.W #9 ,D1
CLR.L DO
NEXT: ADD.L (A0),D0
ADDQ.L #4,A0
DBRA Dl,NEXT
10.
NEXT:
MOVE.L
MOVE.W
CLR.L
ADD.L
DBRA
#$2000,A0
#9,D1
DO
(A0)+,D0
Dl,NEXT
11.
NEXT:
FINI:
CLR.L
LEA
TST.B
BEQ
ADDQ.L
BRA
DO
MYSTR,A0
(A0) +
FINI
#1 ,D0
NEXT
12. No, it is incremented or decremented by 1, 2, or 4, depending on
whether the size was byte, word, or longword.
13. Only address register indirect with postincrementing for both the
source and destination operands.
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