% limb manual
% msb64(3)
% limb 0.1.0
% 2023-07-24
# NAME
msb64 - return the position of the most significant bit set
# SYNOPSIS
#include <limb/uint64.h>
```pre hl
int msb64(u64 <em>val</em>)
```
# DESCRIPTION
The `msb64`() function returns the position of the last (most significant) bit
set in `val`.
The least significant bit is position 1 and the most significant bit is
position 64.
# RETURN VALUE
`msb64`() returns the position of the most significant bit set (from 1 to 64),
or 0 if no bits are set (i.e. `val` is zero).