Why are drivers and firmwares almost always written in C or ASM and not C++?

Question

I am just curious why drivers and firmwares almost always are written in C or Assembly, and not C++?

I have heard that there is a technical reason for this.

Answer 1

because from system level, drivers need to control every bits of every bytes of the memory, other higher language cannot do that, or cannot do that natively, only C/Asm achieve~