Hi friends!, well, I have VHDL code attach (so simply), and I'd like add two operations more, CALL and RETURN, so I need Stack Pointer (SP) [register], it must be point at the end of the memory and stack should start at high addresses and as it grows move to lower addresses, the SP in memory will be store programcounter where jump when return. I use this simple memory file (also attach). How I can do it?, I dont know how save programcounter in memory pointed by sp. Thanks in advance, and sorry, i'm newbie.