Assembly Programming (III)
                     Lecturer: Annie Guo
        S2, 2006          COMP9032 Week6             1
                       Lecture Overview
         • Stack and stack operations
         • Functions and function calls
             – Calling conventions
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                                          Stack
            •  What is stack?
                – A data structure in which the data item that is Last In is 
                   First Out (LIFO)
            •  In AVR, a stack is implemented as a block of 
               consecutive bytes in the SRAM memory
            •  A stack has at least two parameters:
                – Bottom                                                      Bottom-n
                – Stack pointer
                                                    SP
                                                      Bottom
            S2, 2006                     COMP9032 Week6                             3
                        Stack Bottom
         • The stack usually grows from higher 
           addresses to lower addresses
         • The stack bottom is the location with the 
           highest address in the stack
         • In AVR, 0x0060 is the lowest address for 
           stack                    0x0060
               • i.e. in AVR, 
                stack bottom >=0x0060
                                     SP
                                    RAMEND
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