TMS570LC4357: Where does the assigned value of IF2CMD/IF1CMD came from

Part Number: TMS570LC4357

Hello,

I have two Questions:

First one: i'm trying to send can-message with different DLC. I implemented 2 functions to read and to update the DLC.

But i dont know exactly wich CMD i have to use. can someone tells me, how the IF2CMD/IF1CMD-value are built.

2nd question:Ist it possible to make an Unittest with the "Halgogen safeTI Halcogen-CSP" or any other tools my two

implemented functions

void CAN_UpdateDLC (canBASE_t *P_Node, UINT32 P_MessageBox, UINT8 P_Length) {


         while ((P_Node->IF1STAT & 0x80U) ==0x80U);
         P_Node->IF1MCTL &=0xFFFFFFF0;  // Clear the actual configured length of the messagebox
         P_Node->IF1MCTL |= (uint32)P_Length;

         P_Node->IF1CMD  = (uint8) 0xF8U;
         P_Node->IF1NO = (uint8) P_MessageBox;
         /** - Wait until data are copied into IF1 */
         while ((P_Node->IF1STAT & 0x80U) ==0x80U);   

 }

 UINT8 CAN_GetDLC (canBASE_t *P_Node, UINT32 P_MessageBox) {
     UINT8 size;
     while ((P_Node->IF2STAT & 0x80U) ==0x80U)
     {
     } 
     P_Node->IF2CMD = 0x20U;

     /** - Copy data into IF2 */

     P_Node->IF2NO = (uint8) P_MessageBox;

     /** - Wait until data are copied into IF2 */
     while ((P_Node->IF2STAT & 0x80U) ==0x80U)
     {
     } /* Wait */

     size = P_Node->IF2MCTL & 0xFU;
     return size;
 }