.ORIG x3000

Main    LD R6, Stack    ; Initialize the stack and
        LD R5, Stack    ; frame pointers

        LD R0, Param1
        LD R1, Param2

        PUSH R1         ; Pushing the parameters
        PUSH R0         ;

        JSR IntAdd      ; Call the callee

        POP R0          ; Retrieve the return value
        ADD R6, R6, #2  ; Get rid of the parameters
        HALT

IntAdd  ADD R6, R6, #-1 ; Allocate return value
        PUSH R7         ; Store return address
        PUSH R5         ; Store dynamic link
        ADD R5, R6, #-1 ; Setting up frame pointer
        ADD R6, R6, #-1 ; One local variable

        LDR R3, R5, #4  ; Loads A
        LDR R4, R5, #5  ; Loads B

        ADD R3, R3, R4  ; Actually add

        STR R3, R5, #3  ; Store return value

        ADD R6, R6, #1  ; Get rid of locals
        POP R5          ; Restore the dynamic link
        POP R7          ; Restore the return address
        RET

Stack  .FILL x4000
Param1 .FILL x0002
Param2 .FILL x0003

        .END