Basic Characteristics RAPID

Basic Characteristics RAPID Backward execution
10 Backward execution
A program can be executed backwards one instruction at a time. The following general
restrictions are valid for backward execution:
10.1 Backward handlers
- The instructions IF, FOR, WHILE and TEST cannot be executed backwards.
- It is not possible to step backwards out of a routine when reaching the beginning
of the routine.
Procedures may contain a backward handler that defines the backward execution of a
procedure call.
The backward handler is really a part of the procedure and the scope of any routine data
also comprises the backward handler of the procedure.
Example: PROC MoveTo ()
MoveL p1,v500,z10,tool1;
MoveL p2,v500,z10,tool1;
MoveL p3,v500,z10,tool1;
BACKWARD
MoveL p3,v100,z10,tool1;
MoveL p2,v100,z10,tool1;
MoveL p1,v100,z10,tool1;
ENDPROC
When the procedure is called during forward execution, the following occurs:
PROC MoveTo ()
.. MoveL p1,v500,z10,tool1;
MoveTo; MoveL p2,v500,z10,tool1;
.. MoveL p3,v500,z10,tool1;
BACKWARD
MoveL p3,v100,z10,tool1;
MoveL p2,v100,z10,tool1;
MoveL p1,v100,z10,tool1;
ENDPROC
RAPID Reference Manual 5-37