515
APPENDIX B Overview of Instructions
higher byte of the address is 00
H
and the lower byte is specified by the operand. The bit
position at the address is specified by the lower three bits of the operation code.
Figure B.2-3 "Example of bit direct addressing" shows an example.
Figure B.2-3 Example of bit direct addressing
H
Index addressing
Index addressing is indicated by @IX+off in the instruction list. This addressing is used to
access the entire 64-KB area. In this addressing mode, the address is the value resulting from
sign-extending the contents of the first operand and adding them to IX (index register). Figure
B.2-4 "Example of index addressing" shows an example.
Figure B.2-4 Example of index addressing
H
Pointer addressing
Pointer addressing is indicated by @EP in the instruction list. This addressing is used to access
the entire 64-KB area. In this addressing mode, the address is contained in EP (extra pointer).
Figure B.2-5 "Example of pointer addressing" shows an example.
Figure B.2-5 Example of pointer addressing
H
General-purpose register addressing
General-purpose register addressing is indicated by Ri in the instruction list. This addressing is
used to access a register bank in the general-purpose register area. In this addressing mode,
the higher byte of the address is always 01 and the lower byte is specified based on the
contents of RP (register bank pointer) and the lower three bits of the operation code. Figure
B.2-6 "Example of general-purpose register addressing" shows an example.
Figure B.2-6 Example of general-purpose register addressing
H
Immediate addressing
Immediate addressing is indicated by #d8 in the instruction list. This addressing is used when
SETB 34
H
: 2
X X X X X 1 XX
B
0 0 3 4
H
7 6 5 4 3 2 1 0
2 7 F F
H
2 8 0 0
H
MOVW A, @IX+5 A
H
1 2 3 4
H
A
1 2
H
3 4
H
2 7 A5
H
IX
2 7 A5
H
2 7 A6
H
MOVW A, @EP
1 2 3 4
H
A
1 2
H
3 4
H
2 7 A 5
H
EP
0 1 5 6
H
MOV A, R 6
AB
H
A
AB
H
0 1 0 1 0
B
RP