Placing Program into L3

I need to load parts of my application into L3.

It has been suggested to use the following pragmas to map code or data to external memory:

#pragma section (“seg_ext_code”)

#pragma section (“seg_ext_data”)

#pragma section (“seg_ext_pmda”)

I do not see these sections defined in my project(app.ldf). 

Where are these sections defined?

Thanks,

-Steve