<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
<html>
|
<!-- This file documents the GNU Assembler "as".
|
|
Copyright (C) 1991-2021 Free Software Foundation, Inc.
|
|
Permission is granted to copy, distribute and/or modify this document
|
under the terms of the GNU Free Documentation License, Version 1.3
|
or any later version published by the Free Software Foundation;
|
with no Invariant Sections, with no Front-Cover Texts, and with no
|
Back-Cover Texts. A copy of the license is included in the
|
section entitled "GNU Free Documentation License".
|
-->
|
<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ -->
|
<head>
|
<title>Using as: Flonums</title>
|
|
<meta name="description" content="Using as: Flonums">
|
<meta name="keywords" content="Using as: Flonums">
|
<meta name="resource-type" content="document">
|
<meta name="distribution" content="global">
|
<meta name="Generator" content="makeinfo">
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
<link href="index.html#Top" rel="start" title="Top">
|
<link href="AS-Index.html#AS-Index" rel="index" title="AS Index">
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
<link href="Numbers.html#Numbers" rel="up" title="Numbers">
|
<link href="Sections.html#Sections" rel="next" title="Sections">
|
<link href="Bignums.html#Bignums" rel="previous" title="Bignums">
|
<style type="text/css">
|
<!--
|
a.summary-letter {text-decoration: none}
|
blockquote.smallquotation {font-size: smaller}
|
div.display {margin-left: 3.2em}
|
div.example {margin-left: 3.2em}
|
div.indentedblock {margin-left: 3.2em}
|
div.lisp {margin-left: 3.2em}
|
div.smalldisplay {margin-left: 3.2em}
|
div.smallexample {margin-left: 3.2em}
|
div.smallindentedblock {margin-left: 3.2em; font-size: smaller}
|
div.smalllisp {margin-left: 3.2em}
|
kbd {font-style:oblique}
|
pre.display {font-family: inherit}
|
pre.format {font-family: inherit}
|
pre.menu-comment {font-family: serif}
|
pre.menu-preformatted {font-family: serif}
|
pre.smalldisplay {font-family: inherit; font-size: smaller}
|
pre.smallexample {font-size: smaller}
|
pre.smallformat {font-family: inherit; font-size: smaller}
|
pre.smalllisp {font-size: smaller}
|
span.nocodebreak {white-space:nowrap}
|
span.nolinebreak {white-space:nowrap}
|
span.roman {font-family:serif; font-weight:normal}
|
span.sansserif {font-family:sans-serif; font-weight:normal}
|
ul.no-bullet {list-style: none}
|
-->
|
</style>
|
|
|
</head>
|
|
<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
|
<a name="Flonums"></a>
|
<div class="header">
|
<p>
|
Previous: <a href="Bignums.html#Bignums" accesskey="p" rel="previous">Bignums</a>, Up: <a href="Numbers.html#Numbers" accesskey="u" rel="up">Numbers</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="AS-Index.html#AS-Index" title="Index" rel="index">Index</a>]</p>
|
</div>
|
<hr>
|
<a name="Flonums-1"></a>
|
<h4 class="subsubsection">3.6.2.3 Flonums</h4>
|
<a name="index-flonums"></a>
|
<a name="index-floating-point-numbers"></a>
|
<a name="index-constants_002c-floating-point"></a>
|
|
<a name="index-precision_002c-floating-point"></a>
|
<p>A <em>flonum</em> represents a floating point number. The translation is
|
indirect: a decimal floating point number from the text is converted by
|
<code>as</code> to a generic binary floating point number of more than
|
sufficient precision. This generic floating point number is converted
|
to a particular computer’s floating point format (or formats) by a
|
portion of <code>as</code> specialized to that computer.
|
</p>
|
<p>A flonum is written by writing (in order)
|
</p><ul>
|
<li> The digit ‘<samp>0</samp>’.
|
(‘<samp>0</samp>’ is optional on the HPPA.)
|
|
</li><li> A letter, to tell <code>as</code> the rest of the number is a flonum.
|
<kbd>e</kbd> is recommended. Case is not important.
|
|
<p>On the H8/300 and Renesas / SuperH SH architectures, the letter must be
|
one of the letters ‘<samp>DFPRSX</samp>’ (in upper or lower case).
|
</p>
|
<p>On the ARC, the letter must be one of the letters ‘<samp>DFRS</samp>’
|
(in upper or lower case).
|
</p>
|
<p>On the HPPA architecture, the letter must be ‘<samp>E</samp>’ (upper case only).
|
</p>
|
</li><li> An optional sign: either ‘<samp>+</samp>’ or ‘<samp>-</samp>’.
|
|
</li><li> An optional <em>integer part</em>: zero or more decimal digits.
|
|
</li><li> An optional <em>fractional part</em>: ‘<samp>.</samp>’ followed by zero
|
or more decimal digits.
|
|
</li><li> An optional exponent, consisting of:
|
|
<ul>
|
<li> An ‘<samp>E</samp>’ or ‘<samp>e</samp>’.
|
</li><li> Optional sign: either ‘<samp>+</samp>’ or ‘<samp>-</samp>’.
|
</li><li> One or more decimal digits.
|
</li></ul>
|
|
</li></ul>
|
|
<p>At least one of the integer part or the fractional part must be
|
present. The floating point number has the usual base-10 value.
|
</p>
|
<p><code>as</code> does all processing using integers. Flonums are computed
|
independently of any floating point hardware in the computer running
|
<code>as</code>.
|
</p>
|
|
|
|
</body>
|
</html>
|
