@Override
	public long getValue(ParserWalker walker) throws MemoryAccessException {
		long leftval = getLeft().getValue(walker);
		long rightval = getRight().getValue(walker);
		return leftval & rightval;
	}
Form a new expression by ANDing two PatternExpressions
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/app/plugin/processors/sleigh/expression/AndExpression.java