How do I set an interrupt input change in TMCL?

The short program below demonstrates how to set the interrupt on an input change in TMCL. The behavior of this program is the same as EX0008. Depending on the status of Port IN_0, motor 0 turns right (IN_0 = 0) or left (IN_0 = 1).

Before use: Restore Factory Defaults. 
// *** Values that have to be adapted *** // 
amax = 1000                     //max. acceleration (0 ... 2047) 
vmax = 2000                     //max. speed (0 ... 2047) 
cmax = 100                      //max. current (0 ... 255) 
 
// *** Initialization / Set up axis parameter *** // 
SAP 5, 0, amax                  //set max. acceleration 
SAP 6, 0, cmax                  //set max. current 
 
// *** Interrupt initialization *** // 
VECT 39, changeRotation         //define the interrupt vector for input change 0 interrupt (IN_0) 
SGP 39, 3, 3                    //configure interrupt to trigger on both edge of input 0 (0=off,1=low-high,2=high-low,3=both) 
EI 39                           //enable input change 0 interrupt (IN_0) 
EI 255                          //globally switch on interrupt processing 
 
// *** Main Loop *** // 
loop:                           //infinite loop 
       JA loop                  //jump to loop 
 
changeRotation: 
       GIO 0, 0                 //read IN_0 
       COMP 0                   //compare with 0 
       JC EQ, turnRight         //if equal jump to turn right R 
       ROL 0, vmax              //if not equal turn left at vmax 
       RETI                     //end of interrupt 
turnRight: 
       ROR 0, vmax              //turn right at vmax 
RETI