catid

Bitslice(7)            2122196 us; cnt = 15730702
Bitslice(24)           1957533 us; cnt = 15730702
Lauradoux               878497 us; cnt = 15730702
Skipping SSE2 timings; not compiled for that architecture
Skipping SSSE3 timing; not compiled for that architecture.
16-bit LUT             1558676 us; cnt = 15730702
8-bit LUT              2762595 us; cnt = 15730702
popcount               1215033 us; cnt = 15730702
popcountll              427195 us; cnt = 15730702
FreeBSD version 1      4423153 us; cnt = 15730702

catid

// Get the next bit to flip to produce the 8-bit Gray code at the provided index
// Precondition: index > 0 and index < 256
static int GetBitFlipForGrayCode8(int index)
{
   if (index & 1)
      return 0;

   if (index & 15)
      return (0x6764 >> (index & 14)) & 3;

catid

// Get the next bit to flip to produce the 8-bit Gray code at the provided index
// Precondition: index > 0 and index < 256
static int GetBitFlipForGrayCode8(int index)
{
   if (index & 1)
      return 0;

   if (index & 15)
      return (0x6764 >> (index & 14)) & 3;