Change compiler option flags for double precision floating point custom instruction

Thank You very much for the reply

I'm using several steps to get the double values into the custom instruction.

for instance the operation A+B (dataa and datab are input operand to custom instruction) :

1. set the 64 bits value of A to dataa and datab. the custom instruction concatenate the data back to 64 bit and save it to an internal register.

2. set the 64 bits value of B to dataa and datab and process with the addition.

3. when the additon is done, read the upper 32 bit of the result.

4. read the lower 32 bits of the result.

I'm not very good in coding assembler language, do you have any links or documents that can help me ?

By the way in NIOSII IDE Version 10.1 an option was given in the GUI to change the Compier flags (please see attachement).

Thank you in advance.