22
Interrupt Functions Section 1-4
Countermeasure for Above Problem
Interrupting Writing
Multiple Words of Data
Flow of Processing
Processing was interrupted for BSET when #1234 was not yet written to
DM 0010. Therefore, in the comparison at point *1, the contents of DM 0000
and DM 0001 are not equal and processing stops with A in the OFF state. As
a result, although the contents of DM 0000 and DM 0010 agree at the value
INT
100
000
000
ADD
DM0000
#0001
DM0000
INT
200
000
000
Main Program
Interrupts disabled.
Interrupts enabled.
BSET
#1234
DM0000
DM0010
CMP
DM0000
DM0010
Interrupt SubroutineMain Program
25506 (=)
A
#1234 moved to DM 0000.
1234
DM0000
1234
#1234 moved to DM 0001.
DM 0000 read.
DM 0010 read.
DM 0000 compared to DM 0010.
Comparison result output.
Processing interrupted.
#1234 moved to DM 0002.
#1234 moved to DM 0010.
Processing restarted.
Interrupt processing completed.
Processing
of BSET
003E
1234
DM0001
0502
DM0002
1234
0502
ABCD
DM0010
ABCD
ABCD
OFF
A
OFF
1234 OFF
Processing of CMP
(*2)
(*1)
1234 1234 1234
Interrupt occurs
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