may be implemented as a write of each individual sub-value,
in any order.
</p>

<p>
A read <i>r</i> of a memory location <i>x</i>
holding a value
that is not larger than a machine word must observe
some write <i>w</i> such that <i>r</i> does not happen before <i>w</i>
and there is no write <i>w'</i> such that <i>w</i> happens before <i>w'</i>
and <i>w'</i> happens before <i>r</i>.