fls64(9) find last set bit in a 64-bit word

SYNOPSIS

int fls64(__u64 x);

ARGUMENTS

x

the word to search

DESCRIPTION

This is defined in a similar way as the libc and compiler builtin ffsll, but returns the position of the most significant set bit.

fls64(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 64.

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