SV *mi64_right(self, other, rev = &PL_sv_no)
    SV *self
    SV *other
    SV *rev
CODE:
    int64_t a;
    uint64_t b;
    if (SvTRUE(rev)) {
        a = SvI64(aTHX_ other);
        b = SvU64x(self);
    }
    else {
        a = SvI64x(self);
        b = SvU64(aTHX_ other);
    }