From: Paul Eggert Date: Thu, 9 Jul 2020 15:40:17 +0000 (-0700) Subject: Mention floating rounding issues X-Git-Tag: emacs-27.1-rc1~39 X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=1f52771fd3;p=emacs.git Mention floating rounding issues * doc/lispref/numbers.texi (Float Basics): Mention floating-point rounding issues uncovered by the discussion in Bug#42417. --- diff --git a/doc/lispref/numbers.texi b/doc/lispref/numbers.texi index 4002b36ce50..f018ef4c7c0 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{-})