SignExtendedNumber opMul(const SignExtendedNumber a) const
{
    //  like 0x10 * 0x10 == 0x100 == 0.

    /* Special handling for zeros:
    */
}

unittest
{
    if (Port.isNan(r1) || Port.isNan(r2)) // if unordered
    {
    }

    while (cur && cur.ty == Tsarray) // sizes of dimensions
    {
        TypeSArray sa = cast(TypeSArray) cur;
        mangleNumber(sa.dim ? sa.dim.toInteger() : 0);
        cur = cur.nextOf();
    }
}