[SAOC Milestone 1, Task 2]

+ Update README.
+ Document rtoslink.d hooks for the monitor implementation.

README.md

@@ -30,13 +30,13 @@ This is the light weight D runtime - it is a barebones runtime targeting ARM Cor
 19. Static constructors and destructors (opt-in by version `LWDR_ModuleCtors`)
 20. Shared static constructors and destructor (opt-in by version `LWDR_ModuleCtors`)
 21. Module info (opt-in by version `LWDR_ModuleCtors`)
+22. Object monitors (opt in by version `LWDR_Sync`)
+23. Shared and sychronized (opt in by version `LWDR_Sync`)
 
 ### What doesn't work?
-22. Exceptions and Throwables (experimental implementation was removed)
-23. There is no GC implementation (primitive memory tracking is now available with `LWDR_TrackMem`, `RefCount!T` and `Unique!T` are now available)
-24. Associative arrays
-25. Object monitors (Milestone 1, Task 2)
-26. Shared/synchronised (Milestone 1, Task 2)
+24. Exceptions and Throwables (experimental implementation was removed)
+25. There is no GC implementation (primitive memory tracking is now available with `LWDR_TrackMem`, `RefCount!T` and `Unique!T` are now available)
+26. Associative arrays
 
 ### Which compilers can be used?
 LDC works the best. DMD is not compatible. GDC will work but points 18-21 inclusive aren't supported.

source/rtoslink.d

@@ -37,12 +37,19 @@ these hooks depending on what is requested of the runtime by user code.
 
 	version(LWDR_Sync)
 	{
+		/// Called when LWDR wants to create a mutex.
 		void* rtosbackend_mutexInit();
+		/// Called when LWDR wants to destroy a mutex.
 		void rtosbackend_mutexDestroy(void*);
+		/// LWDR wants to lock a mutex (eg, via synchronized).
 		void rtosbackend_mutexLock(void*);
+		/// LWDR wants to unlock a mutex (eg, via synchronized).
 		void rtosbackend_mutexUnlock(void*);
+		/// Attempt to lock a mutex. Returns 0 if couldn't, 1 if locked.
 		int rtosbackend_mutexTryLock(void*);
+		/// LWDR stores a single, global mutex for its own implementation. This function creates it. Called on runtime start.
 		void* rtosbackend_globalMutexInit();
+		/// Destroy LWDR's global mutex. Called on runtime shutdown.
 		void rtosbackend_globalMutexDestroy(void*);
 	}
 }