Setup pre-emption

[Rob Gries]

• Project 4 - #33
  • include/proc.h
  • include/queue.h
  • system/main.c - A "main program" for testing scheduling.
  • system/queue.c - An implementation of the queue data structure.
  • system/create.c - A partial function for creating a new process.
  • system/ctxsw.S - An incomplete assembly routine for switching process contexts.
  • system/ready.c - A function for adding a process to the ready queue.
  • system/resched.c - The primary scheduling code, equivalent to yield().
  • system/getstk.c - A rudimentary function for dynamically allocating new stacks for new processes.
• Add PIT device driver for context switch - #44
• Implement syscalls
  • Create - #33
  • Kill
  • Yield
  • Resume/Suspend
    * [ ] Arbitrary number of arguments
    * [ ] Enter Ring3

[Rob Gries]

I decided to postpone usermode. There's higher priority items to implement first