protected long getOffsetFromFlat(long flat, int segment) {
		return flat - (segment << 4);
	}
Given a flat address offset, extract a segment offset assuming a
specific segment value.
@param flat is the flat offset
@param segment is the specific segment value
@return the segment offset
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/address/SegmentedAddressSpace.java