fix

static VALUE
BigDecimal_fix(VALUE self)
{
    ENTER(5);
    Real *c, *a;
    size_t mx;

    GUARD_OBJ(a, GetVpValue(self, 1));
    mx = a->Prec *(VpBaseFig() + 1);
    GUARD_OBJ(c, VpCreateRbObject(mx, "0"));
    VpActiveRound(c, a, VP_ROUND_DOWN, 0); /* 0: round off */
    return ToValue(c);
}