1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<!-- This file documents the GNU Assembler "as". 4 5Copyright (C) 1991-2021 Free Software Foundation, Inc. 6 7Permission is granted to copy, distribute and/or modify this document 8under the terms of the GNU Free Documentation License, Version 1.3 9or any later version published by the Free Software Foundation; 10with no Invariant Sections, with no Front-Cover Texts, and with no 11Back-Cover Texts. A copy of the license is included in the 12section entitled "GNU Free Documentation License". 13 --> 14<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ --> 15<head> 16<title>Using as: Literal Directive</title> 17 18<meta name="description" content="Using as: Literal Directive"> 19<meta name="keywords" content="Using as: Literal Directive"> 20<meta name="resource-type" content="document"> 21<meta name="distribution" content="global"> 22<meta name="Generator" content="makeinfo"> 23<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 24<link href="index.html#Top" rel="start" title="Top"> 25<link href="AS-Index.html#AS-Index" rel="index" title="AS Index"> 26<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> 27<link href="Xtensa-Directives.html#Xtensa-Directives" rel="up" title="Xtensa Directives"> 28<link href="Literal-Position-Directive.html#Literal-Position-Directive" rel="next" title="Literal Position Directive"> 29<link href="Transform-Directive.html#Transform-Directive" rel="previous" title="Transform Directive"> 30<style type="text/css"> 31<!-- 32a.summary-letter {text-decoration: none} 33blockquote.smallquotation {font-size: smaller} 34div.display {margin-left: 3.2em} 35div.example {margin-left: 3.2em} 36div.indentedblock {margin-left: 3.2em} 37div.lisp {margin-left: 3.2em} 38div.smalldisplay {margin-left: 3.2em} 39div.smallexample {margin-left: 3.2em} 40div.smallindentedblock {margin-left: 3.2em; font-size: smaller} 41div.smalllisp {margin-left: 3.2em} 42kbd {font-style:oblique} 43pre.display {font-family: inherit} 44pre.format {font-family: inherit} 45pre.menu-comment {font-family: serif} 46pre.menu-preformatted {font-family: serif} 47pre.smalldisplay {font-family: inherit; font-size: smaller} 48pre.smallexample {font-size: smaller} 49pre.smallformat {font-family: inherit; font-size: smaller} 50pre.smalllisp {font-size: smaller} 51span.nocodebreak {white-space:nowrap} 52span.nolinebreak {white-space:nowrap} 53span.roman {font-family:serif; font-weight:normal} 54span.sansserif {font-family:sans-serif; font-weight:normal} 55ul.no-bullet {list-style: none} 56--> 57</style> 58 59 60</head> 61 62<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> 63<a name="Literal-Directive"></a> 64<div class="header"> 65<p> 66Next: <a href="Literal-Position-Directive.html#Literal-Position-Directive" accesskey="n" rel="next">Literal Position Directive</a>, Previous: <a href="Transform-Directive.html#Transform-Directive" accesskey="p" rel="previous">Transform Directive</a>, Up: <a href="Xtensa-Directives.html#Xtensa-Directives" accesskey="u" rel="up">Xtensa Directives</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> 67</div> 68<hr> 69<a name="literal"></a> 70<h4 class="subsubsection">9.55.5.4 literal</h4> 71<a name="index-literal-directive"></a> 72 73<p>The <code>.literal</code> directive is used to define literal pool data, i.e., 74read-only 32-bit data accessed via <code>L32R</code> instructions. 75</p> 76<div class="smallexample"> 77<pre class="smallexample"> .literal <var>label</var>, <var>value</var>[, <var>value</var>…] 78</pre></div> 79 80<p>This directive is similar to the standard <code>.word</code> directive, except 81that the actual location of the literal data is determined by the 82assembler and linker, not by the position of the <code>.literal</code> 83directive. Using this directive gives the assembler freedom to locate 84the literal data in the most appropriate place and possibly to combine 85identical literals. For example, the code: 86</p> 87<div class="smallexample"> 88<pre class="smallexample"> entry sp, 40 89 .literal .L1, sym 90 l32r a4, .L1 91</pre></div> 92 93<p>can be used to load a pointer to the symbol <code>sym</code> into register 94<code>a4</code>. The value of <code>sym</code> will not be placed between the 95<code>ENTRY</code> and <code>L32R</code> instructions; instead, the assembler puts 96the data in a literal pool. 97</p> 98<p>Literal pools are placed by default in separate literal sections; 99however, when using the ‘<samp>--text-section-literals</samp>’ 100option (see <a href="Xtensa-Options.html#Xtensa-Options">Command-line Options</a>), the literal 101pools for PC-relative mode <code>L32R</code> instructions 102are placed in the current section.<a name="DOCF3" href="#FOOT3"><sup>3</sup></a> 103These text section literal 104pools are created automatically before <code>ENTRY</code> instructions and 105manually after ‘<samp>.literal_position</samp>’ directives (see <a href="Literal-Position-Directive.html#Literal-Position-Directive">literal_position</a>). If there are no preceding 106<code>ENTRY</code> instructions, explicit <code>.literal_position</code> directives 107must be used to place the text section literal pools; otherwise, 108<code>as</code> will report an error. 109</p> 110<p>When literals are placed in separate sections, the literal section names 111are derived from the names of the sections where the literals are 112defined. The base literal section names are <code>.literal</code> for 113PC-relative mode <code>L32R</code> instructions and <code>.lit4</code> for absolute 114mode <code>L32R</code> instructions (see <a href="Absolute-Literals-Directive.html#Absolute-Literals-Directive">absolute-literals</a>). These base names are used for literals defined in 115the default <code>.text</code> section. For literals defined in other 116sections or within the scope of a <code>literal_prefix</code> directive 117(see <a href="Literal-Prefix-Directive.html#Literal-Prefix-Directive">literal_prefix</a>), the following rules 118determine the literal section name: 119</p> 120<ol> 121<li> If the current section is a member of a section group, the literal 122section name includes the group name as a suffix to the base 123<code>.literal</code> or <code>.lit4</code> name, with a period to separate the base 124name and group name. The literal section is also made a member of the 125group. 126 127</li><li> If the current section name (or <code>literal_prefix</code> value) begins with 128“<code>.gnu.linkonce.<var>kind</var>.</code>”, the literal section name is formed 129by replacing “<code>.<var>kind</var></code>” with the base <code>.literal</code> or 130<code>.lit4</code> name. For example, for literals defined in a section named 131<code>.gnu.linkonce.t.func</code>, the literal section will be 132<code>.gnu.linkonce.literal.func</code> or <code>.gnu.linkonce.lit4.func</code>. 133 134</li><li> If the current section name (or <code>literal_prefix</code> value) ends with 135<code>.text</code>, the literal section name is formed by replacing that 136suffix with the base <code>.literal</code> or <code>.lit4</code> name. For example, 137for literals defined in a section named <code>.iram0.text</code>, the literal 138section will be <code>.iram0.literal</code> or <code>.iram0.lit4</code>. 139 140</li><li> If none of the preceding conditions apply, the literal section name is 141formed by adding the base <code>.literal</code> or <code>.lit4</code> name as a 142suffix to the current section name (or <code>literal_prefix</code> value). 143</li></ol> 144 145<div class="footnote"> 146<hr> 147<h4 class="footnotes-heading">Footnotes</h4> 148 149<h3><a name="FOOT3" href="#DOCF3">(3)</a></h3> 150<p>Literals for the 151<code>.init</code> and <code>.fini</code> sections are always placed in separate 152sections, even when ‘<samp>--text-section-literals</samp>’ is enabled.</p> 153</div> 154<hr> 155<div class="header"> 156<p> 157Next: <a href="Literal-Position-Directive.html#Literal-Position-Directive" accesskey="n" rel="next">Literal Position Directive</a>, Previous: <a href="Transform-Directive.html#Transform-Directive" accesskey="p" rel="previous">Transform Directive</a>, Up: <a href="Xtensa-Directives.html#Xtensa-Directives" accesskey="u" rel="up">Xtensa Directives</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> 158</div> 159 160 161 162</body> 163</html> 164