e mostly platform-specific code in <TT>dyn_load.c</tt>.
</ul> 
The marker maintains an explicit stack of memory regions that are known
to be accessible, but that have not yet been searched for contained pointers.
Each stack entry contains the starting address of the block to be scanned,
as well as a descriptor of the block.  If no layout information is
available for the block, then the descriptor is simply a length.
(For other possibilities, see <TT>gc_mark.h</tt>.)
<P>
At the beginning of the mark phase, a