private AddressSet findUnviewableAddressRanges() {
		// check the address every "minimum gap size" which should find any gaps
		// bigger than that gap size.  The minimum gap size is about 1% of the total
		// addresses, so this should loop about 100 times.
		BigInteger stepSize = addressToIndexMap.getMiniumUnviewableGapSize();
		BigInteger indexCount = addressToIndexMap.getIndexCount();

		AddressSet addressSet = new AddressSet();

		BigInteger index = BigInteger.ZERO;
		while (index.compareTo(indexCount) < 0) {
			checkIndex(index, addressSet);
			index = index.add(stepSize);
		}
		return addressSet;
	}
Attempts to find a field location for the given address from the given program location
@param address the address to try and get a layout for.
@param location the location contains other information needed to generate a field
location
@param useDefaultLocation if true, will return a generic location for this address
if no field has a specific match.  Otherwise, will return null if no fields have
an exact match.
@return a field location for the given address.
Ghidra/Features/Base/src/main/java/ghidra/app/util/viewer/listingpanel/ListingModelAdapter.java