Section 4: Programming 276

Miscellaneous Program Topics

Program Debugging

lncluding Temporary Stops. Where space permits it is advisable to include additional R/S operations in long programs to display intermediate results while writing and checking the program. When the program is finally checked out, the unwanted stops can be deleted.
Single Stepping. When switched to RUN mode, SST executes the program, one step at a time. You can observe the effect of your program in slow motion. To single step through a top row key function in a program, first press GTO followed by A, . . . , E, then press SST, repeatedly. However, the RTN the end of the function will be ignored. (Also see Figure 4-2.)
Numerical Examples. It is usually necessary to work out a sample problem by independent means and then to do the same calculation using your program.

Magnetic Cards

Prerecorded Cards. Now that you have seen how programs work you can understand that the answers to the following question depends on the program:
“During a program stop, can I use the stack, the other registers, the flags, etc?”
It is safest to follow the printed procedures when using the prerecorded programs. Departures should not be made without studying the program listing in detail.
Read/Write Operations. Reading or writing a card does not change the contents of the registers. A program can utilize data developed by a prior program. Whenever a magnetic card is written or read, all 100 steps are transferred. In most cases, the display will blink and program memory will be cleared to gNOP codes if a read operation fails. Reading a blank card will have the same effect.