The return address is saved onto the top of your stack when you use statement LCALL FUNC. When returning from FUNC this address is poped back from the stack i.e. when RET instruction is fetched

However there is no address saving when using jumps such as LJMP FUNC. and if you use RET in a jump your micro will pop some errorneous thing from stack and program will most probably hang or behave errorneous.

By default your stack is initialised or starts at location 08H in Internal RAM. You can set the stack start i.e. stack pointer at any RAM location by using following statement.

MOV SP,#xxxxh


Regards
Prahlad Purohit