From 1f52771fd3ec79937626e7a3a71ad4427d07e31c Mon Sep 17 00:00:00 2001
From: Paul Eggert
Date: Thu, 9 Jul 2020 08:40:17 -0700
Subject: [PATCH] Mention floating rounding issues
* doc/lispref/numbers.texi (Float Basics): Mention floating-point
rounding issues uncovered by the discussion in Bug#42417.
---
doc/lispref/numbers.texi | 3 +++
1 file changed, 3 insertions(+)
diff --git a/doc/lispref/numbers.texi b/doc/lispref/numbers.texi
index 4002b36ce5..f018ef4c7c 100644
--- a/doc/lispref/numbers.texi
+++ b/doc/lispref/numbers.texi
@@ -227,6 +227,9 @@ you are using. On all computers supported by Emacs, this is
and is discussed further in David Goldberg's paper
``@url{https://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html,
What Every Computer Scientist Should Know About Floating-Point Arithmetic}''.
+On modern platforms, floating-point operations follow the IEEE-754
+standard closely; however, results are not always rounded correctly on
+some obsolescent platforms, notably 32-bit x86.
The read syntax for floating-point numbers requires either a decimal
point, an exponent, or both. Optional signs (@samp{+} or @samp{-})
--
GitLab