INT 14 - COMM-DRV v14.0 - SET USER INTERRUPT ROUTINE AH = 8Bh CX = bitmask of interrupt to process 00h = deinstall BX:DI -> DWORDDoubleword; four bytes. Commonly used to hold a 32-bit segment:offset or selector:offset address. containing address of function to be called Return: AH bit 7 clear if successful AH bit 7 set on error