Initial revision of ARM simulator and (empty) MIPS simulator.

runtime/vm/os.h

Index: runtime/vm/os.h
===================================================================
--- runtime/vm/os.h	(revision 17504)
+++ runtime/vm/os.h	(working copy)
@@ -78,6 +78,14 @@
   // Sleep the currently executing thread for millis ms.
   static void Sleep(int64_t millis);
 
+  // Debug break.
+  static void DebugBreak();
+
+  static uword NullPageSize() { return null_page_size_; }

[Ivan Posva, 2013/01/24 18:25:57]

I am not sure what we need this for.

[regis, 2013/01/24 21:47:48]

Good point. Since we do not install handlers for segmentation violations, the
simulator can implement null checks independently of the actual page size.
Removed.

+  static bool IsInsideNullPage(intptr_t offset) {
+    return static_cast<uword>(offset) < null_page_size_;
+  }
+
   // Print formatted output to stdout/stderr for debugging.
   static void Print(const char* format, ...) PRINTF_ATTRIBUTE(1, 2);
   static void PrintErr(const char* format, ...) PRINTF_ATTRIBUTE(1, 2);
@@ -124,6 +132,10 @@
   static void Abort();
 
   static void Exit(int code);
+
+ private:
+  // Cache the null page size.
+  static uword null_page_size_;
 };
 
 }  // namespace dart