the address about the in-system memory

I have used Megawizard generated a 1024x16bit ram, how can I know the absolute address of this ram? And If I written a value to an absolute address of this ram, how can I know it works? Since I want to write a program which is to write a value to anaddress in the ram in C language. And there is another program, when I put a counter hex fire as the fire of the memory content data during generate the ram, after synthesis to FPGA, I use the in-system memory content edit tool, I find the data in the in-system memory are all 0. I used continuoused read data from memory. I don't know why. Does someone knows why? Thanks.