mak,

As you know the 8052 architecture provides for indirect access to the IRAM above 80H. This is an ideal area for the stack (providing you are using a '52).

Keep in mind that the stack pointer increments prior to use so if your intended stack area starts at 80H you would init to 7FH, commonly using a constant such as:

stack_base  equ  80H-1

also you should watch you stack pointer as you develop your solution to avoid problems and to get a feel for the run time "nesting". If you are using any form of monitor, ICE, or simulator this is fairly easy and will save you quite a bit of grief.

regards,
p