;;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