User's Manual

HARSFEN0602
5.6.8 Killing The Call Stack
In some rare situations, it is desirable to exit a function without returning to its return
address. The reset instruction solves this problem by emptying the call stack before making
a jump.
Syntax:
reset <JUMP_NAME>
The valid jump after the ‘reset’ keyword is one of the following:
1. label
2. auto routine
3. user function with no defined input arguments
All other expression or absence of expression after the keyword ‘reset’ is illegal.
Remark: Label in reset instruction must be global. Local label is illegal, because the stack will be
emptied and all local variables and return address of the function to whose the local label belongs
will be erased.
Example:
Assume that an Amplifier (an axis) runs a programmed routine.
An inspection station may assert a “Product defective” digital signal.
The “Product defective” signal is coupled to the digital in#1 input.
An automatic routine is coupled to the digital in#1 input, to stop the part assembly and get ready for the
assembly of the next part.
##START_NEW **Label for starting a new part
… **Working code
… **Last line of working code
#@AUTO_I1 **Subroutine label
PA=0;BG **Return axis to origin
reset START_NEW **Clear the stack and go to the beginning
The reset in the #@AUTO_I1 routine is required since we do not know if any function calls are
executing when Digital In #1 is asserted. If a function was executing, the reset prevents junk
gathering in the call stack. Otherwise, the call stack was empty and the reset does no harm. Note that
after the reset control does not return to the function which was executing before Digital In# is
occurred. Stack was cleared and the return address to the interrupted function was removed from the
stack.
Note
The #@AUTO_I1 routine is executed after the work code is done for every assembled part.
The program proceeds from the last line of the working code to PA=0;BG, which resets the
machine for another part assembly. The next instruction is a reset to the START_NEW
label.
5.6.9 Automatic subroutines
5.6.9.1 List Of Automatic Routines
A special kind of routine is the auto routine. These routines are executed automatically