Simplify integer arithmetic code.

runtime/platform/utils.h

Index: runtime/platform/utils.h
===================================================================
--- runtime/platform/utils.h	(revision 3410)
+++ runtime/platform/utils.h	(working copy)
@@ -86,22 +86,25 @@
   static uint32_t WordHash(word key);
 
   // Check whether an N-bit two's-complement representation can hold value.
-  static inline bool IsInt(int N, word value) {
-    ASSERT((0 < N) && (N < kBitsPerWord));
+  template<typename T>
+  static inline bool IsInt(int N, T value) {
+    ASSERT((0 < N) && (N < (kBitsPerByte * sizeof(T))));

[Ivan Posva, 2012/01/18 20:05:22]

sizeof(value) is closer to the style guide:
http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml#sizeof

[regis, 2012/01/18 21:50:12]

Done.

     word limit = static_cast<word>(1) << (N - 1);

[Ivan Posva, 2012/01/18 20:05:22]

You need to cast the 1 to T instead of word here. And the type of limit needs to
change as well. Can you please add the appropriate tests for 64-bit values which
would have failed here on a 32-bit platform. Thanks!

[regis, 2012/01/18 21:50:12]

The cast is fixed in patch 5.
I have added a test.

     return (-limit <= value) && (value < limit);
   }
 
-  static inline bool IsUint(int N, word value) {
-    ASSERT((0 < N) && (N < kBitsPerWord));
+  template<typename T>

[Ivan Posva, 2012/01/18 20:05:22]

ditto

[regis, 2012/01/18 21:50:12]

Done.

+  static inline bool IsUint(int N, T value) {
+    ASSERT((0 < N) && (N < (kBitsPerByte * sizeof(T))));
     word limit = static_cast<word>(1) << N;
     return (0 <= value) && (value < limit);
   }
 
   // Check whether the magnitude of value fits in N bits, i.e., whether an
   // (N+1)-bit sign-magnitude representation can hold value.
-  static inline bool IsAbsoluteUint(int N, word value) {
-    ASSERT((0 < N) && (N < kBitsPerWord));
+  template<typename T>

[Ivan Posva, 2012/01/18 20:05:22]

ditto

[regis, 2012/01/18 21:50:12]

Done.

+  static inline bool IsAbsoluteUint(int N, T value) {
+    ASSERT((0 < N) && (N < (kBitsPerByte * sizeof(T))));
     if (value < 0) value = -value;
     return IsUint(N, value);
   }