About this task
If the program check was due to an arithmetic error (interruption
codes 7 through F), you need to find the operands used in the last
instruction.
Procedure
- Use the procedure described in section Locating program data to locate the fields.
- Check that the operands are valid.
You need
to know a little about the type of arithmetic being done, so that
you can verify the operands are correct. The interrupt you received
tells you what sort of arithmetic the system was doing (binary, packed
decimal, or floating point), but you need to determine if that is
what you had intended to do. You might need to consult a programming
language manual if you have any queries about this.
- When you have identified the operands, you need to decide
where the problem is.
Questions to consider include:
- Has the data been overlaid?
- Has the value been changed by faulty logic?
- Does the data type not match the operation type? For example,
if you define the variable as being packed decimal and then you read
in binary information, this causes a ‘data exception’
error.