Sanatorium Times


CCPU: 16-bit virtual CPU

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Markus "Notch" Persson is indirectly responsible for this one. After Minecraft became immensely successful, he started another game called "0x10c". And he stated that he wanted that game to include simulated virtual 16 bit CPUs. After looking at the DCPU specification which he had published I thought about doing something very similar. The end result I was dreaming up would be an almost sandbox like robot construction and multiplayer shooting game where the players must also come up with the control software for their creations. And the software would run on a simulated virtual 16-bit computer including memory, harddrive, custom operating systems and everything.

Of course, this is far too ambitious and probably not even fun. However, I created an instruction set for a 16 bit CPU called "CCPU" (well, guess where that name came from...). I managed to get as far as writing a simulator VM for it including hard drive images and a framebuffer for graphical output. There's also an assembler included, but nothing in terms of an actual operating system on top of that. Writing that stuff basically from scratch and in assembler to start is just tedious.

It also turned out that designing a CPU around 16 bit words is not the most clever thing in the world if the instruction set can't cope with anything else and doesn't even have bit shift operations. Even writing to the 8 bit framebuffer with 2 pixels packed in each 16 bit words is very cumbersome in this setup. That's why I set this design aside and created CCPU-2, which is a different (and better) story.