bresenham dx dy sx sy

    ld (color), a
    ld ix, 0
    add ix, sp
    ld bc, 0
    ld hl, 0
    ld l, (ix+0)
    ld h, (ix+1)
    ld c, (ix+3)
    ld b, (ix+4)
    ld a, c
    ld (x), a
    ld a, b
    ld (x+1), a
    or a
    sbc hl, bc
    jp p, +_
    ld a, -1
    ld (sx), a
    jr ++_
_:
    ld a, 1
    ld (sx), a
_:
    ex de, hl
    call _abs24de
    push hl
    ld hl, 0
    ld bc, 0
    ld l, (ix+2)
    ld c, (ix+5)
    ld a, c
    ld (y), a
    or a
    sbc hl, bc
    jp p, +_
    ld a, -1
    ld (sy), a
    jr ++_
_:
    ld a, 1
    ld (sy), a
_:
    ex de, hl
    call _abs24de
    push hl