toolchain/share/doc/as.html/GNU-Assembler.html

77 lines
3.6 KiB
HTML

<html lang="en">
<head>
<title>GNU Assembler - Using as</title>
<meta http-equiv="Content-Type" content="text/html">
<meta name="description" content="Using as">
<meta name="generator" content="makeinfo 4.13">
<link title="Top" rel="start" href="index.html#Top">
<link rel="up" href="Overview.html#Overview" title="Overview">
<link rel="prev" href="Manual.html#Manual" title="Manual">
<link rel="next" href="Object-Formats.html#Object-Formats" title="Object Formats">
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
<!--
This file documents the GNU Assembler "as".
Copyright (C) 1991-2019 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''.
-->
<meta http-equiv="Content-Style-Type" content="text/css">
<style type="text/css"><!--
pre.display { font-family:inherit }
pre.format { font-family:inherit }
pre.smalldisplay { font-family:inherit; font-size:smaller }
pre.smallformat { font-family:inherit; font-size:smaller }
pre.smallexample { font-size:smaller }
pre.smalllisp { font-size:smaller }
span.sc { font-variant:small-caps }
span.roman { font-family:serif; font-weight:normal; }
span.sansserif { font-family:sans-serif; font-weight:normal; }
--></style>
</head>
<body>
<div class="node">
<a name="GNU-Assembler"></a>
<p>
Next:&nbsp;<a rel="next" accesskey="n" href="Object-Formats.html#Object-Formats">Object Formats</a>,
Previous:&nbsp;<a rel="previous" accesskey="p" href="Manual.html#Manual">Manual</a>,
Up:&nbsp;<a rel="up" accesskey="u" href="Overview.html#Overview">Overview</a>
<hr>
</div>
<h3 class="section">1.2 The GNU Assembler</h3>
<!-- man begin DESCRIPTION -->
<p><span class="sc">gnu</span> <samp><span class="command">as</span></samp> is really a family of assemblers.
If you use (or have used) the <span class="sc">gnu</span> assembler on one architecture, you
should find a fairly similar environment when you use it on another
architecture. Each version has much in common with the others,
including object file formats, most assembler directives (often called
<dfn>pseudo-ops</dfn>) and assembler syntax.
<p><a name="index-purpose-of-_0040sc_007bgnu_007d-assembler-23"></a><samp><span class="command">as</span></samp> is primarily intended to assemble the output of the
<span class="sc">gnu</span> C compiler <code>gcc</code> for use by the linker
<code>ld</code>. Nevertheless, we've tried to make <samp><span class="command">as</span></samp>
assemble correctly everything that other assemblers for the same
machine would assemble.
Any exceptions are documented explicitly (see <a href="Machine-Dependencies.html#Machine-Dependencies">Machine Dependencies</a>).
<!-- This remark should appear in generic version of manual; assumption -->
<!-- here is that generic version sets M680x0. -->
This doesn't mean <samp><span class="command">as</span></samp> always uses the same syntax as another
assembler for the same architecture; for example, we know of several
incompatible versions of 680x0 assembly language syntax.
<!-- man end -->
<p>Unlike older assemblers, <samp><span class="command">as</span></samp> is designed to assemble a source
program in one pass of the source file. This has a subtle impact on the
<kbd>.org</kbd> directive (see <a href="Org.html#Org"><code>.org</code></a>).
</body></html>