Clemens,

The stack works as LIFO and the current address was not affected.
This means, on pushing, SP was incremented before
writing the byte.
So after reset (SP = 07h) the 1. push store the byte at address 08h.

Please watch that every poped location was immediately destroyed
by the next call or interrupt.
So if you want getting data from the stack without overwriting,
you must use indirect adressing by R0 or R1.
e.g.
mov r0, sp
mov a, @r0


Peter