Nios II memory location of a variable

Hi,

I am using Quartus 14.1 and I am trying to write a test application for DDR3 connected to Nios II. I have successfully created the hardware and synthesized. And I want to do some write/read tests on DDR3 using Nios. First, I create an array named write_data and write it to DDR location 0. Then, I read the DDR starting from location 0 into an array named read_data. However, when I check the pointers of elements of write_data and read_data, I see their addresses are in the same address space as DDR. Does it mean that these variables already on the DDR? I want them to be in onchip memory actually. Is there any way to declare variables in memory space I want?

Thanks.

Efe