quoted from here:

_function: 
    push ebp       ;store the old base pointer 
    mov ebp, esp   ;make the base pointer point to the current 
                   ;stack location – at the top of the stack is the  
                   ;old ebp, followed by the return address and then 
                   ;the parameters. 
    sub esp, x     ;x is the size, in bytes, of all 
                   ;"automatic variables" in the function 

What's stored in esp in the above code snippet?