chipsfb_bitblt
sc->sc_gc.gc_bitblt = chipsfb_bitblt;
chipsfb_bitblt(sc, x, y, x, y, wi, he, ROP_NOT_DST);
chipsfb_bitblt(sc, x, y, x, y, wi, he, ROP_NOT_DST);
chipsfb_bitblt(sc, xs, y, xd, y, width, height, ROP_COPY);
chipsfb_bitblt(sc, x, ys, x, yd, width, height, ROP_COPY);
static void chipsfb_bitblt(void *, int, int, int, int,