NiosII beginer .. Help with instruction PLZ

Hello mates !

I am using Quartus 13.0 web edition and niosII 13.0 also. It is my first time

I managed to creat my Qsys and run Hello world sample.

I need to creat my own code. My questions are :

How can i know all the instructions that can be used in NiosII such as "IORD_ALTERA_AVALON_PIO_DATA" // "IOWR_ALTERA_AVALON_PIO_DATA" ? is there any doc to refer to ?

Thank u