OO_CHARS
opl_set_op_reg(sc, OPL_AM_VIB, v, 0, p->ops[OO_CHARS+0]);
opl_set_op_reg(sc, OPL_AM_VIB, v, 1, p->ops[OO_CHARS+1]);
chars0 = p->ops[OO_CHARS+0];
chars1 = p->ops[OO_CHARS+1];