;drawing line from 2 cordinates
.proc line
testing:
    ;#  (X_pos, Y_pos)                                 #
    ;#                     *                               #
    ;#                         *                           #
    ;#                             *                       #
    ;#                                (X_end, Y_end)       #
    ;
    ; NOTE THAT X_pos <= X_end and line is going downwords   max 45deg!

    ;Not values but register position in memory
    X_end = $04
    Y_end = $05
    X_pos = $FC
    Y_pos = $FB
    dy = $06
    dx = $07
    D = $08


    ;Set values
    LDA #$00
    STA $FD ; for pixel_draw

    ;example values ~~~~~ SHOULD BE PRECOMPILED
    LDA #$00
    STA X_pos
    STA Y_pos

    LDA #$50
    STA X_end
    STA dx
    LDA #$40
    STA Y_end
    STA dy
    LDA #($40 + $40 - $50 )
    STA D ; = 2*dy - dx
    ; ~~~~~~~

    for_x:
        jsr pixel_draw
        LDY D ; FOR DEBUG

        ; If D <= 0  then: skipp
        LDX D;
        DEX
        BMI case_2
        case_1:
        INC Y_pos


        ;D = D_before -2*dx
        LDA dx
        ROL A
        TAX
        LDA D
        STX D ; D = -2*dx, A = D_before
        SEC
        SBC D ; A = D_before -2*dx
        STA D;
        jmp last
        case_2:
        ;D = D + 2*dx
        LDA dx
        ROL
        CLC
        ADC D
        STA D
        last:
        CMP #$00
       ; increment x untill x == large
        INC X_pos
        LDA X_pos
        CMP #199
        BEQ end
        JMP for_x
    end:
    jmp testing

   .endproc