@Override
	public void setRegisterValue(RegisterValue value) {
		Register reg = value.getRegister();
		if (!reg.isProcessorContext()) {
			throw new UnsupportedOperationException();
		}
		if (contextRegValue == null) {
			contextRegValue = value.getBaseRegisterValue();
		}
		else {
			contextRegValue = contextRegValue.combineValues(value);
		}
	}
Set those bits in the nonFlowingContextRegisterMask which should not 
flow with context.
@param reg context register piece
Ghidra/Framework/Emulation/src/main/java/ghidra/pcode/emulate/EmulateDisassemblerContext.java