diff options
Diffstat (limited to 'doc/lispref/numbers.texi')
| -rw-r--r-- | doc/lispref/numbers.texi | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/doc/lispref/numbers.texi b/doc/lispref/numbers.texi index 3fdc94169bd..5058063af4d 100644 --- a/doc/lispref/numbers.texi +++ b/doc/lispref/numbers.texi @@ -1107,6 +1107,19 @@ bit is one in the result if, and only if, the @var{n}th bit is zero in @end example @end defun +@cindex popcount +@cindex Hamming weight +@cindex counting set bits +@defun logcount integer +This function returns the @dfn{Hamming weight} of @var{integer}: the +number of ones in the binary representation of @var{integer}. + +@example +(logcount 42) ; 42 = #b101010 + @result{} 3 +@end example +@end defun + @node Math Functions @section Standard Mathematical Functions @cindex transcendental functions |