[lld] r199156 - Add comment to bit manipulation functions.

[Rui Ueyama]

Author: ruiu
Date: Mon Jan 13 16:29:16 2014
New Revision: 199156

URL: http://llvm.org/viewvc/llvm-project?rev=199156&view=rev
Log:
Add comment to bit manipulation functions.

Modified:
    lld/trunk/include/lld/ReaderWriter/RelocationHelperFunctions.h

Modified: lld/trunk/include/lld/ReaderWriter/RelocationHelperFunctions.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/include/lld/ReaderWriter/RelocationHelperFunctions.h?rev=199156&r1=199155&r2=199156&view=diff
==============================================================================
--- lld/trunk/include/lld/ReaderWriter/RelocationHelperFunctions.h (original)
+++ lld/trunk/include/lld/ReaderWriter/RelocationHelperFunctions.h Mon Jan 13 16:29:16 2014
@@ -12,32 +12,36 @@
 
 namespace lld {
 
-/// \brief Return the bits that are described by the mask
-template < typename T >
-T gatherBits(T val, T mask)
-{
+/// Gather val's bits as specified by the mask. Example:
+///
+///  Val:    0bABCDEFGHIJKLMN
+///  Mask:   0b10111100001011
+///  Output: 0b000000ACDEFKMN
+template <typename T> T gatherBits(T val, T mask) {
   T result = 0;
   size_t off = 0;
 
-  for (size_t bit = 0; bit != sizeof (T) * 8; ++bit) {
+  for (size_t bit = 0; bit != sizeof(T) * 8; ++bit) {
     const bool valBit = (val >> bit) & 1;
     const bool maskBit = (mask >> bit) & 1;
     if (maskBit) {
-      result |= static_cast <T> (valBit) << off;
+      result |= static_cast<T>(valBit) << off;
       ++off;
     }
   }
   return result;
 }
 
-/// \brief Set the bits as described by the mask
-template <typename T>
-T scatterBits(T val, T mask)
-{
+/// Scatter val's bits as specified by the mask. Example:
+///
+///  Val:    0bABCDEFG
+///  Mask:   0b10111100001011
+///  Output: 0b00ABCD0000E0FG
+template <typename T> T scatterBits(T val, T mask) {
   T result = 0;
   size_t off = 0;
 
-  for (size_t bit = 0; bit != sizeof (T) * 8; ++bit) {
+  for (size_t bit = 0; bit != sizeof(T) * 8; ++bit) {
     const bool valBit = (val >> off) & 1;
     const bool maskBit = (mask >> bit) & 1;
     if (maskBit) {