Debugging in Menu Mode › Activity Screens › At Screen

At Screen

Purpose

You can use the At screen to:

• Add breakpoints
• Modify breakpoints
• Delete breakpoints
• Inquire about the breakpoints that have already been set

As explained in "Debugger features", Chapter 1, breakpoint temporarily halts processing, allowing you to examine the results of execution up to the point of interruption.

'Remember': Processing is halted before the instruction at the breakpoint is executed.

The AT command can be used in both the setup and runtime phases of the debugger.

Two Sections

The specification area of the At screen has two separate sections:

• The first section sets new breakpoints:

  ADD BREAKPOINT AT:
  
  BEFORE: MAX        AFTER: 0           EVERY: 1
  

• The second section inquires about existing breakpoints, or deletes them:

  OTHER ACTION.......:   (I-INQUIRE/D-DELETE/G-IGNORE)
  BREAKPOINT OR <ALL>:
  

• Both sections modify breakpoints

You can specify both sections of the screen at the same time.

Field Options

These are the field options for this area:

ADD BREAKPOINT AT:

Designates the location in your program that will contain a breakpoint. The specified value can include one or more debug expressions resolving to an address that contains a valid instruction or, for CA ADS dialogs, a valid CME.

Remember: It is not valid to set a breakpoint at the target of an Assembler execute (EX) instruction.

BEFORE: MAX

Specifies the execution pause on encountering the instruction up to, but not including, the specified number of times. The default (MAX) is to pause as many times as the instruction is encountered.

AFTER: 0

Specifies that the debugger will pause at the breakpoint after the instruction has been executed the specified number of times. The default (0) is to start pausing when the instruction is first encountered.

EVERY: 1

Specifies an execution pause every time the counter for the breakpoint instruction reaches a multiple of the value specified. The default (1) is to pause every time the instruction is encountered.

Tip: If you don't change the defaults, the debugger will pause each time the breakpoint instruction is encountered.

OTHER ACTION...: (I-INQUIRE/D-DELETE/G-IGNORE)

• I requests a listing of the breakpoint location and characteristics
• D removes the breakpoint
• G bypasses the breakpoint but increments the breakpoint counter

BREAKPOINT OR <ALL>:

Indicates the breakpoints affected by the Other Action field. You can indicate a specific breakpoint (that is, a debug-expression), or specify that the action applies to ALL breakpoints within the current program or dialog.