Re: lognot

[Paul Eggert <eggert@cs.ucla.edu>]

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Richard Stallman wrote:
> The doc string of lognot should explain what it does with large integers.

I installed the attached patch to make that clearer.

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From 495d0667fcf4df9f10c261684162c64f08aadd71 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Wed, 31 Jul 2019 06:56:14 -0700
Subject: [PATCH] Clarify (lognot bignum)

* doc/lispref/numbers.texi (Bitwise Operations):
Say that (= (lognot n) (- -1 n)).
---
 doc/lispref/numbers.texi | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/doc/lispref/numbers.texi b/doc/lispref/numbers.texi
index cae8babcb4..0c71387a8a 100644
--- a/doc/lispref/numbers.texi
+++ b/doc/lispref/numbers.texi
@@ -1072,7 +1072,8 @@ Bitwise Operations
 @defun lognot integer
 This function returns the bitwise complement of its argument: the @var{n}th
 bit is one in the result if, and only if, the @var{n}th bit is zero in
-@var{integer}, and vice-versa.
+@var{integer}, and vice-versa.  The result equals @minus{}1 @minus{}
+@var{integer}.
 
 @example
 (lognot 5)
-- 
2.17.1