Revised GetPowerOfTwo32() and GetPowerOfTwo64() to be more efficient.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@963 6f19259b-4bc3-4df7-8a09-765794883524

MdePkg/Library/BaseLib/GetPowerOfTwo32.c

@@ -33,8 +33,9 @@ GetPowerOfTwo32 (
   IN      UINT32                    Operand
   )
 {
-  INTN                              BitPos;
-  
-  BitPos = HighBitSet32 (Operand);
-  return BitPos >= 0 ? 1ul << BitPos : 0;
+  if (Operand == 0) {
+    return 0;
+  }
+
+  return 1ul << HighBitSet32 (Operand);
 }

MdePkg/Library/BaseLib/GetPowerOfTwo64.c

@@ -33,8 +33,9 @@ GetPowerOfTwo64 (
   IN      UINT64                    Operand
   )
 {
-  INTN                              BitPos;
+  if (Operand == 0) {
+    return 0;
+  }
 
-  BitPos = HighBitSet64 (Operand);
-  return BitPos >= 0 ? LShiftU64 (1, BitPos) : 0;
+  return LShiftU64 (1, HighBitSet64 (Operand));
 }