High−level Instructions
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Usage example: Computing the elapsed time
The elapsed time can be computed using the F158 (CSUB) instruction.
Using the calendar timer, store the starting time and ending time in the data memory, and compute the
elapsed time between the two values. An example in which operation was stopped at 08:02:15 and resumed
at 10:30:25 will be used to show how the time that operation was stopped is computed.
The computation can be thought of as subtracting 08:02:15 from 10:30:25.
BCD H code
94122308
S1+2 S1+1
0215
S1
Years Months Days Hours Minutes Seconds
Starting time: December 23, 1994 8: 2’ 15”
BCD H code
94122310
S2+2 S2+1
3025
S2
Years Months Days Hours Minutes Seconds
Ending time: December 23, 1994 10: 30’ 25”
The data to be subtracted is taken from the starting time data, as shown below.
BCD H code
00080215
Hours Minutes Seconds
(8: 02’ 15”)
BCD H code
94122302
DT32 DT31
2810
DT30
Years Months Days Hours Minutes Seconds
Result: December 23, 1994 2: 28’ 10”
F158 (CSUB) execution
The section indicating
the “Day” is set to “0”.
The results will be as follows.
The section indicating the hour, minutes and seconds is read as ”2 hours, 28 minutes, 10 seconds”, and this is
the elapsed time.
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