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77 lines
3.6 KiB
HTML
77 lines
3.6 KiB
HTML
4 years ago
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<html lang="en">
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<head>
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<title>GNU Assembler - Using as</title>
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<meta http-equiv="Content-Type" content="text/html">
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<meta name="description" content="Using as">
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<meta name="generator" content="makeinfo 4.13">
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<link title="Top" rel="start" href="index.html#Top">
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<link rel="up" href="Overview.html#Overview" title="Overview">
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<link rel="prev" href="Manual.html#Manual" title="Manual">
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<link rel="next" href="Object-Formats.html#Object-Formats" title="Object Formats">
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<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
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<!--
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This file documents the GNU Assembler "as".
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Copyright (C) 1991-2015 Free Software Foundation, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3
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or any later version published by the Free Software Foundation;
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with no Invariant Sections, with no Front-Cover Texts, and with no
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Back-Cover Texts. A copy of the license is included in the
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section entitled ``GNU Free Documentation License''.
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-->
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<meta http-equiv="Content-Style-Type" content="text/css">
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<style type="text/css"><!--
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pre.display { font-family:inherit }
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pre.format { font-family:inherit }
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pre.smallformat { font-family:inherit; font-size:smaller }
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pre.smallexample { font-size:smaller }
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pre.smalllisp { font-size:smaller }
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span.sc { font-variant:small-caps }
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span.roman { font-family:serif; font-weight:normal; }
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span.sansserif { font-family:sans-serif; font-weight:normal; }
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--></style>
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</head>
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<body>
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<div class="node">
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<a name="GNU-Assembler"></a>
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<p>
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Next: <a rel="next" accesskey="n" href="Object-Formats.html#Object-Formats">Object Formats</a>,
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Previous: <a rel="previous" accesskey="p" href="Manual.html#Manual">Manual</a>,
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Up: <a rel="up" accesskey="u" href="Overview.html#Overview">Overview</a>
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<hr>
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</div>
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<h3 class="section">1.2 The GNU Assembler</h3>
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<!-- man begin DESCRIPTION -->
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<p><span class="sc">gnu</span> <samp><span class="command">as</span></samp> is really a family of assemblers.
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If you use (or have used) the <span class="sc">gnu</span> assembler on one architecture, you
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should find a fairly similar environment when you use it on another
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architecture. Each version has much in common with the others,
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including object file formats, most assembler directives (often called
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<dfn>pseudo-ops</dfn>) and assembler syntax.
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<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
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<span class="sc">gnu</span> C compiler <code>gcc</code> for use by the linker
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<code>ld</code>. Nevertheless, we've tried to make <samp><span class="command">as</span></samp>
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assemble correctly everything that other assemblers for the same
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machine would assemble.
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Any exceptions are documented explicitly (see <a href="Machine-Dependencies.html#Machine-Dependencies">Machine Dependencies</a>).
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<!-- This remark should appear in generic version of manual; assumption -->
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<!-- here is that generic version sets M680x0. -->
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This doesn't mean <samp><span class="command">as</span></samp> always uses the same syntax as another
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assembler for the same architecture; for example, we know of several
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incompatible versions of 680x0 assembly language syntax.
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<!-- man end -->
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<p>Unlike older assemblers, <samp><span class="command">as</span></samp> is designed to assemble a source
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program in one pass of the source file. This has a subtle impact on the
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<kbd>.org</kbd> directive (see <a href="Org.html#Org"><code>.org</code></a>).
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</body></html>
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