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CHAPTER 3 CPU
Figure 3.7-6 Example of AL-AH Transfer in the Accumulator (A) (16 Bits, Register Indirect)
MOVW A,@RW1+6
A before execution
A after execution
●
Accumulator byte-processing arithmetic operation
When a byte-processing arithmetic operation instruction is executed for the AL register, the upper 8 bits of
the AL register before the arithmetic operation is executed are ignored. The upper 8 bits of the arithmetic
operation results are all zeros.
●
Initial value of the accumulator
The initial value after a reset is undefined.
44
(Instruction that performs a word-length read using the result of
the RW1 contents + an 8-bit offset as the address and stores the
read value in the A register)
XXXX
1234
H
H
DTB
A6
H
1234
2B52
H
H
AH
AL
Memory space
MSB
8F
H
A61540
H
2B
A6153E
H
H
+6
15
RW1
H
LSB
74
H
52
H
38
H
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