FLS(9) Basic C Library Functions FLS(9)NAMEfls - find last set bit in word
SYNOPSIS
int fls(int x);
ARGUMENTS
x
the word to search
DESCRIPTION
This is defined in a similar way as the libc and compiler builtin ffs,
but returns the position of the most significant set bit.
fls(value) returns 0 if value is 0 or the position of the last set bit
if value is nonzero. The last (most significant) bit is at position 32.
COPYRIGHTKernel Hackers Manual 3.11 November 2013 FLS(9)