If you are using 8051s with less than 2K memory as replacement for a few digital gates then there's no doubt that you're programming in assembly language.

But this thread wants to discuss if the object-oriented paradigm is in the future of embedded design and the answer everywhere is a resounding yes. The best-selling book "Object Oriented Analysis and Design with Applications" by Grady Booch amazingly had most of his examples in embedded systems.