@Override
	public void decode(Decoder decoder) throws DecoderException {
		int el = decoder.openElement(ELEM_CONTEXT_PAT);
		maskvalue = new PatternBlock(true);
		maskvalue.decode(decoder);
		decoder.closeElement(el);
	}
Pattern which depends only on the non-instruction stream bits
of the context
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/app/plugin/processors/sleigh/pattern/ContextPattern.java