SPI SLAVE PROGRAMMING HELP!

we have just started working on nios so the question which i am going to post may look stupid but will be great help for us if u reply soon.

once i design spi slave on SOPC do i need to specify the spi logic in nios ide software like do i need to specify the instructions for spi registers the command for read and write data or these protocol directly becomes the part of system as soon as we define it.

if we have to define the logic for spi slave in ide then can u suggest where we can find a working code for demonstration and can we simulate the design in quartus before downloading it on board

thanks in advance

ashish