PS/2 Keyboard driver

The problem was, that I mistook the IRQ number for the interrupt vector when calling my own function!
Now I can start expanding my keyboard driver. Currently, it already prints the pressed keys to the screen, as you can see on the screen shot.

Performance improvements when scrolling

After I finished the interrupt stuff, I can focus on improving the TTY in other areas, like the performance. I am using now memset() and memcpy() functions when scrolling the frame buffer, which itself is not an improvement: I optimized the two functions to use copy 8-byte blocks ad uint64_t instead of each byte individually, which made a significant difference. Scrolling with KVM acceleration is now almost instant on my PC, and without it is as fast as it was before with acceleration.

Road map

I want to improve the TTY with things like buffering, which should improve the performance even more.
When I have a solid TTY, I can rework the demo and ship again.