@Override
	public Register getRegister(int opIndex) {

		if (opIndex < 0 || opIndex >= getNumOperands()) {
			return null;
		}

		lock.acquire();
		try {
			checkIsValid();
			return proto.getRegister(opIndex, this);
		}
		finally {
			lock.release();
		}
	}
Get the original context used to establish the shared prototype
@param baseContextReg is a context register
@return prototype context value
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/code/InstructionDB.java