Vector table in ROM memory

The gcc map files give me a strong feeling that installing ISR vectors consumes lots of data memory. The library function _nr_installuserisr uses a static allocated buffer for registrating isr vectors. This buffer resides in data memory and is copied into vector memory, which is located in a different memory segment ( system is defined using prog_mem, data_mem, vector_mem).

I prefer to use fixed vectors in prog_mem (ROM) and not use the _nr_installuserisr. The documentation mentions this possibility but I cannot find any detailed description on this.

Does anybody have documentation covering this or can give me some directions.

Thanks in advance.

Regards