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Increment/Decrement Instructions Section 3-10
The Equals Flag will be turned ON if the result is 0000 and the Carry Flag will
be turned ON when a digit changes from 9 to 0.
Both the Equals Flag and the Carry Flag will be turned ON when the content
of Wd changes from 9999 to 0000.
Flags
Precautions The content of Wd must be BCD. If it is not BCD, an error will occur and the
Error Flag will be turned ON.
Examples Operation of ++B(594)
In the following example, the BCD content of D00100 will be incremented by 1
every cycle as long as CIO 000000 is ON.
Operation of @++B(594)
The up-differentiated variation is used in the following example, so the content
of D00100 will be incremented by 1 only when CIO 000000 has gone from
OFF to ON.
Wd Wd
Name Label Operation
Error Flag ER ON if the content of Wd is not BCD.
OFF in all other cases.
Equals Flag = ON if the content of Wd is 0000 after execution.
OFF in all other cases.
Carry Flag CY ON if a digit in Wd went from 9 to 0 during execution.
OFF in all other cases.
D00100 D00100
Increment Increment Increment
Increment
Wd: Wd:
: Execution of ++B(594)
Incremented every cycle
while CIO 000000 is ON.
@++B
D00100 D00100
Increment
Increment
Wd: Wd:
: Execution of @++B(594)
Incremented only for
up-differentiation.
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