Important

• This does not run in the latest "vanilla" C++ VM image, g++-multilib has to be installed extra

Makefile

• Added the -std=c++17 flag to enable better constexpr support.
• Removed optimizations as the system would crash with them. The BlueScreen would show an empty callstack on crashes with -O2, so I guess the problem is the missing ebp or something like that.

Changes

• Removed the Input.h/Input.cc files
• Removed the Queue.h/Queue.cc/Chain.h files
• Many changes to the scheduler (strategy is still round robin):
  • Merged dispatcher into the scheduler (removed Dispatch.h/Dispatch.cc)
  • Scheduler no longer uses queue but vector
  • Scheduler owns threads (no outside references)
  • Threads are addressed by tid from the outside
  • Retrieve threads when killing them
  • Threads are deallocated when killed and not retrieved
  • Scheduler manages blocked threads
• Simplified thread switching by storing registers on the stack (removed ThreadState.h, Thread.inc)

Additions

• Some stream manipulators for CGA_Stream (color) and OutStream (fixed width)
• Logging with serial port output
• Main menu to start demos
• A very basic system to broadcast keyboard events to threads
• Basic vector and iterator
• Basic unique_ptr
• Basic fixed size array (just a wrapper for C-style arrays)
• Basic dynamic string (heap allocated)
• Basic span

Bugs

• Can't exit the PCSPKdemo (bluescreen)
• After exiting the VBEdemo the paging isn't reactivated (so the pagefault bluescreen no longer works)
• The PreemptiveThreadDemo LoopThreads can't be exited, the demo can't be launched multiple times
• Tree Allocator (uses a red black tree to find best-fit blocks) crashes when freelist root is removed
• Can't restart the OS (bluescreen)
• Fast keyboard inputs sometimes trigger bluescreens
• Different combinations of demos also trigger bluescreens
• Other seemingly random bluescreens that are hard to pinpoint
• Key event management doesn't differentiate between press/type/release etc.
• Main menu doesn't work with multiple inputs (like holding a key)

Other

• Keyboard repeat rate and led functionality is missing
• Circle functionality in VESA mode is missing
• Singleton can't have a destructor, as C++ doesn't know how to deinitialize them after program exit. This happens because we compile with very limited libraries so "atexit" to register destructors is missing. I wanted to make the device/hardware classes (PCSPK, CPU etc) singleton because it doesn't make sense to have more than one.