Astro8-Computer/example_armstrong_programs/NEGATIVE.arm at main · sam-astro/Astro8-Computer · GitHub

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// Includes
#include "./STACK.arm"


// ///////////////////////////////////////////////////////////
// // This code calls the function called "RegCToNegative". //
// // Similar to "RegCToNegative();" in c++                 //
// // Uncomment this and place it where you want it called  //
// ///////////////////////////////////////////////////////////
//     asm"
//     pcr
//     "
//     add @A,18 -> $_STACK_VAL
//     sub $_STACK_POINTER,1 -> $_STACK_POINTER
//     change *$_STACK_POINTER = $_STACK_VAL
//     goto #RegCToNegative


/////////////////////////////////////////////////////////////////////////////////////////
// This is a function which converts a number to/from a negative using twos compliment //
/////////////////////////////////////////////////////////////////////////////////////////
    #RegCToNegative

    asm"
    swpc
    not
    ldib 1
    add
    swpc
    "

    ///////////////////////////////////////////////////////////////////
    // This is a "return;" statement. It will end function execution //
    // and continue after the above function call                    //
    ///////////////////////////////////////////////////////////////////
        change $_STACK_VAL = *$_STACK_POINTER
        add $_STACK_POINTER,1 -> $_STACK_POINTER
        change @A = $_STACK_VAL
        asm"
        jreg
        "