;-------------------
    ;Instructions
    ;-------------------
    LD R1, STACK_ADDR
    ADD R2, R1, #0
    LD R3, CAPACITY

    LD R6, SUB_STACK_PUSH

    LEA R0, PUSH_PROMPT_MAIN
    PUTS
    PUSH_LOOP_MAIN
        GETC
        OUT
        ADD R0, R0, #-10
        BRz END_PUSH_LOOP_MAIN
        ADD R0, R0, #10
        JSRR R6
        BR PUSH_LOOP_MAIN
    END_PUSH_LOOP_MAIN

    LD R6, SUB_STACK_POP

    LEA R0, POP_PROMPT_MAIN
    PUTS
    POP_LOOP_MAIN
        GETC
        ADD R0, R0, #-10
        BRz END_POP_LOOP_MAIN
        ADD R0, R0, #10
        JSRR R6
        LEA R0, CHAR_POPPED
        PUTS
        BR POP_LOOP_MAIN
    END_POP_LOOP_MAIN


    HALT
    ;-------------------
    ;Local Data
    ;-------------------
    SUB_STACK_PUSH          .FILL       x3200
    SUB_STACK_POP           .FILL       x3400
    STACK_ADDR              .FILL       x5000
    CAPACITY                .FILL       #10
    PUSH_PROMPT_MAIN        .STRINGZ    "Enter a character to push onto the stack (ENTER to stop):\n"
    POP_PROMPT_MAIN         .STRINGZ    "Press any key to pop from back (ENTER to stop):\n"
    CHAR_POPPED             .STRINGZ    "Popped!\n"