boundary scan user defined data registers

[sreenivasaraov]

i have just started reading about jtag boundary scan architecture and need to implement it in an application where jtag port is used to read and write to register banks.For this purpose, I need to add two user defined data registers ( one for reading and writing each).

I want to know how to customize the architecture in order to insert the above said user defined registers .

Also, I need to define two user defined instructions for the same purpose of sending and receiving data from register banks. From my understanding, I presume that can be done by defining these instructions in the BSDL file? Is my understanding correct?