The push-button view on the main window contains push buttons that
  correspond to debugger commands.  You can modify, add, remove, and
  resequence push buttons and the commands associated with them.

  Use the default push buttons to complete the following functions.

   Push
   Button       Function
   ------       --------
   Stop         Interrupts program execution or a debugger
                operation without ending the debugging
                session.

   Go           Starts or resumes execution from the current
                program location.

   Step         Executes the program one step unit of
                execution. By default, this is one executable
                line of source code.

   S-into       (Step into)  When execution is suspended at a
                routine call statement, moves execution into
                the called routine just past the start of the
                routine. If not at a routine call statement,
                this push button has the same behavior as the
                Step push button.

   S-ret        (Step return) Executes the program directly to
                the end of the routine.

   S/call       (Step call) Executes the program to the next
                call or return instruction.

   EX           (Examine) Displays, in the command view,
                the current value of a variable whose name
                you have selected in a window.

   E/az         Displays, in the command view, the current
                value of a variable whose name you have
                selected in a window.  The variable is interpreted
                as a zero-terminated ASCII string.

   E/ac         Displays, in the command view, the current
                value of a variable whose name you have
                selected in a window.  The variable is interpreted
                as a counted ASCII string preceded by a one-byte
                count field that contains the length of the string.

   EVAL         Displays, in the command view, the value
                of a language expression in the current language
                (by default, the language of the module containing
                the main program.

   MON          (Monitor) Displays, in the monitor view, a
                variable name that you have selected in a window
                and the current value of that variable. Whenever the
                debugger regains control from your program, it
                automatically checks the value and updates the
                displayed value accordingly.