Posted: Mon Feb 05, 2007 11:53 pmPosted: Tue Feb 06, 2007 12:12 am| Code: |
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The MONITOR and REVERSE commands are used to activate review mode. Review mode lets you monitor and review the execution path by stepping backwards through your program. You can view the statements that were executed during normal (forward) execution. You can trace backwards through the actual sequence of instructions that led to the current breakpoint and see the data values as they were at the time. There is no guesswork about which of the possible paths the program took; the actual path that was taken during forward execution of the program is displayed. The MONITOR command records the execution history and the REVERSE command enables you to review the execution history. To activate review mode, enter the MONITOR command from the primary command line. MONITOR without a module name records history for the current module1not necessarily the active module that is currently executing, but the module indicated by the program field on the third line. After issuing the MONITOR command, execute the statements you want to review. Then, when your program pauses during logical execution, enter the following primary command: REVERSE The REVERSE command places the execution arrow on the last statement that was executed, and changes the execution direction of your program1from forward to reverse (backward). From this point on, the REVERSE command acts as a toggle that changes the direction in which your program is executed. During review mode, the execution status message on the fourth line of the screen indicates the execution direction and the statement where execution is paused. 1. Entering the REVERSE command only changes the direction of execution; it does not cause execution to occur. 2. You must enter the GO n or GO command to begin execution in the current direction. The GO n command moves the active arrow n lines in the current direction, which lets you step through the program line-by-line. Unlike normal execution mode, a GO n command in review mode ignores module boundaries and will pause after executing n statements, regardless of what modules they are in. It is recommended that you use GO 1 commands to do a backward line-by-line execution. 3. In review mode, TRACE does not recognize the default maximum limit of 25 statements, and continues execution until it encounters the AT INITIAL EXECUTION POSITION. To halt the reverse trace, press the Attn key. |
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