Halting on a line in assembler only if a condition is true

Often a particular part of your program works fine for the first few thousand times, but it fails under certain conditions. Setting a line breakpoint is inefficient because you will have to repeatedly enter the GO command.

Example: sample assembler program for debugging

In the DISPARM program, to stop z/OS® Debugger when the COUNTER variable is set to 3, enter the following command:

AT 78 DO; IF COUNTER ^= 3 THEN GO; END;

Line 78 is the line labeled  BUMPCTR . The command causes z/OS Debugger to stop at line 78. If the value of COUNTER is not 3, the program continues. The command causes z/OS Debugger to stop on line 78 only if the value of COUNTER is 3.