huangmeng
/
Embedded_AI


			
							12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879808182838485868788899091929394
							<!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) 1991-2017 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 5.2, http://www.gnu.org/software/texinfo/ -->
<head>
<title>Using as: Symbol Intro</title>

<meta name="description" content="Using as: Symbol Intro">
<meta name="keywords" content="Using as: Symbol Intro">
<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="Syntax.html#Syntax" rel="up" title="Syntax">
<link href="Statements.html#Statements" rel="next" title="Statements">
<link href="Comments.html#Comments" rel="prev" title="Comments">
<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="Symbol-Intro"></a>
<div class="header">
<p>
Next: <a href="Statements.html#Statements" accesskey="n" rel="next">Statements</a>, Previous: <a href="Comments.html#Comments" accesskey="p" rel="prev">Comments</a>, Up: <a href="Syntax.html#Syntax" accesskey="u" rel="up">Syntax</a> &nbsp; [<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="Symbols-1"></a>
<h3 class="section">3.4 Symbols</h3>

<a name="index-characters-used-in-symbols"></a>
<p>A <em>symbol</em> is one or more characters chosen from the set of all
letters (both upper and lower case), digits and the three characters
&lsquo;<samp>_.$</samp>&rsquo;.
On most machines, you can also use <code>$</code> in symbol names; exceptions
are noted in <a href="Machine-Dependencies.html#Machine-Dependencies">Machine Dependencies</a>.
No symbol may begin with a digit.  Case is significant.
There is no length limit; all characters are significant.  Multibyte characters
are supported.  Symbols are delimited by characters not in that set, or by the
beginning of a file (since the source program must end with a newline, the end
of a file is not a possible symbol delimiter).  See <a href="Symbols.html#Symbols">Symbols</a>.
</p>
<p>Symbol names may also be enclosed in double quote <code>&quot;</code> characters.  In such
cases any characters are allowed, except for the NUL character.  If a double
quote character is to be included in the symbol name it must be preceeded by a
backslash <code>\</code> character.
<a name="index-length-of-symbols"></a>
</p>


</body>
</html>