Looking at uartSample.TCF from the PSP UART EDMA example. I noticed the lines
/* ECM configuration */
bios.HWI.instance("HWI_INT7").interruptSelectNumber = 0;
bios.HWI.instance("HWI_INT8").interruptSelectNumber = 1;
bios.HWI.instance("HWI_INT9").interruptSelectNumber = 2;
bios.HWI.instance("HWI_INT10").interruptSelectNumber = 3;
When I look at the settings for HWI_INT7 using Tconf, I see the function set to _ECM_dispatch and "Use Dispatcher" set to True. Neither of these is the default value and there are no lines in the TCF file where these values are set. This begs the question, "How does it know?" Where do these values come from?