The DM816x's problem of hardware interrupts in SYS/BIOS

The board I am using is  the DM816x development board,and the interrupt is EMAC TX interrupt .The interruptconfiguration in the .cfg file is as shown below.

And my ISR function is as follows.

Void MACTXINT00(UArg arg)
{
System_printf("TX interrupt\n");
}

Finally,the program always run in the interrupt function.So why?

Looking forward to your answer！