U64 nextQuad( U64 **p, U8 o ) {                  // p: pointer to pointer to the 'current' quad; o: value of the unused bits at the beginning.
    U64 hi = *( ++*p )                           // increment the pointer at *p, and set hi to the value it points at.
      , lo = *( *p+1 );                          // and lo to the value + 1 it points at
    return __shiftleft128( lo, hi, o );          // return the value from the higher location with o bits from lo shifted in from the right.
}