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APPENDIX
D.4
Indirect Addressing
In indirect addressing mode, an address is specified indirectly by the address data of an
operand.
■
Indirect Addressing
● Register indirect addressing (@RWj j = 0 to 3)
Memory is accessed using the contents of general-purpose register RWj as an address. Address bits 16 to
23 are indicated by the data bank register (DTB) when RW0 or RW1 is used, system stack bank register
(SSB) or user stack bank register (USB) when RW3 is used, or additional data bank register (ADB) when
RW2 is used.
Figure D.4-1 Example of Register Indirect Addressing (@RWj j = 0 to 3)
MOVW A, @RW1 (This instruction reads data by register indirect addressing and stores
Before execution
After execution
● Register indirect addressing with post increment (@RWj+ j = 0 to 3)
Memory is accessed using the contents of general-purpose register RWj as an address. After operand
operation, RWj is incremented by the operand size (1 for a byte, 2 for a word, or 4 for a long word).
Address bits 16 to 23 are indicated by the data bank register (DTB) when RW0 or RW1 is used, system
stack bank register (SSB) or user stack bank register (USB) when RW3 is used, or additional data bank
register (ADB) when RW2 is used.
If the post increment results in the address of the register that specifies the increment, the incremented
value is referenced after that. In this case, if the next instruction is a write instruction, priority is given to
writing by an instruction and, therefore, the register that would be incremented becomes write data.
600
it in A.)
A 0 7 1 6
RW1 D 3 0 F
A 2 5 3 4 F F E E
RW1 D 3 0 F
2 5 3 4
DTB 7 8
78D30F
78D310
DTB 7 8
Memory space
E E
H
F F
H
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