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94 lines
4.6 KiB
HTML
94 lines
4.6 KiB
HTML
4 years ago
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<html lang="en">
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<head>
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<title>Comments - 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="Syntax.html#Syntax" title="Syntax">
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<link rel="prev" href="Whitespace.html#Whitespace" title="Whitespace">
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<link rel="next" href="Symbol-Intro.html#Symbol-Intro" title="Symbol Intro">
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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.smalldisplay { font-family:inherit; font-size:smaller }
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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="Comments"></a>
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<p>
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Next: <a rel="next" accesskey="n" href="Symbol-Intro.html#Symbol-Intro">Symbol Intro</a>,
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Previous: <a rel="previous" accesskey="p" href="Whitespace.html#Whitespace">Whitespace</a>,
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Up: <a rel="up" accesskey="u" href="Syntax.html#Syntax">Syntax</a>
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<hr>
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</div>
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<h3 class="section">3.3 Comments</h3>
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<p><a name="index-comments-123"></a>There are two ways of rendering comments to <samp><span class="command">as</span></samp>. In both
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cases the comment is equivalent to one space.
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<p>Anything from ‘<samp><span class="samp">/*</span></samp>’ through the next ‘<samp><span class="samp">*/</span></samp>’ is a comment.
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This means you may not nest these comments.
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<pre class="smallexample"> /*
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The only way to include a newline ('\n') in a comment
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is to use this sort of comment.
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*/
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/* This sort of comment does not nest. */
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</pre>
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<p><a name="index-line-comment-character-124"></a>Anything from a <dfn>line comment</dfn> character up to the next newline is
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considered a comment and is ignored. The line comment character is target
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specific, and some targets multiple comment characters. Some targets also have
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line comment characters that only work if they are the first character on a
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line. Some targets use a sequence of two characters to introduce a line
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comment. Some targets can also change their line comment characters depending
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upon command line options that have been used. For more details see the
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<em>Syntax</em> section in the documentation for individual targets.
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<p>If the line comment character is the hash sign (‘<samp><span class="samp">#</span></samp>’) then it still has the
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special ability to enable and disable preprocessing (see <a href="Preprocessing.html#Preprocessing">Preprocessing</a>) and
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to specify logical line numbers:
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<p><a name="index-g_t_0023-125"></a><a name="index-lines-starting-with-_0040code_007b_0023_007d-126"></a><a name="index-logical-line-numbers-127"></a>To be compatible with past assemblers, lines that begin with ‘<samp><span class="samp">#</span></samp>’ have a
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special interpretation. Following the ‘<samp><span class="samp">#</span></samp>’ should be an absolute
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expression (see <a href="Expressions.html#Expressions">Expressions</a>): the logical line number of the <em>next</em>
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line. Then a string (see <a href="Strings.html#Strings">Strings</a>) is allowed: if present it is a
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new logical file name. The rest of the line, if any, should be whitespace.
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<p>If the first non-whitespace characters on the line are not numeric,
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the line is ignored. (Just like a comment.)
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<pre class="smallexample"> # This is an ordinary comment.
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# 42-6 "new_file_name" # New logical file name
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# This is logical line # 36.
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</pre>
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<p>This feature is deprecated, and may disappear from future versions
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of <samp><span class="command">as</span></samp>.
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</body></html>
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