I assume your question is for an integer (called v below) and not an unsigned integer.
int v = 612635685; // whatever value you wishunsigned int get_msb(int v){ int r = 31; // maximum number of iteration until integer has been totally left shifted out, considering that first bit is index 0. Also we could use (sizeof(int)) << 3 - 1 instead of 31 to make it work on any platform. while (!(v & 0x80000000) && r--) { // mask of the highest bit v <<= 1; // multiply integer by 2. } return r; // will even return -1 if no bit was set, allowing error catch}If you want to make it work without taking into account the sign you can add an extra 'v <<= 1;' before the loop (and change r value to 30 accordingly).Please let me know if I forgot anything. I haven't tested it but it should work just fine.