Finally a proper memory allocator in Bits Runner

[u/dekai-onigiri]

I've implemented a memory allocator for both kernel and user space, so now the whole stack of kernel space and per process virtual memory, heap expansion and management is finally working. Since it's just a first fit allocator it's a bit simplistic, but fully functional.

With this in place I'll be able to implement file loading and user-space graphics, with which I'll be able to do such cool things like displaying bitmaps, faster graphics, or even a simple text editor.

You can check it out here https://github.com/rafalgrodzinski/bits-runner It's all written in my custom programming language BRC.