unsigned rev (unsigned x)
{
 x = (x & 0x55555555) << 1 | (x >> 1) & 0x55555555;
 x = (x & 0x33333333) << 2 | (x >> 2) & 0x33333333;
 x = (x & 0x0F0F0F0F) << 4 | (x >> 4) & 0x0F0F0F0F;
 x = (x <<24) | ((x & 0xFF00) <<8) |
     ((x >> 8) & 0xFF00) | (x >> 24);
 return x;
}

Прошу прощение.