aarch64-linux-gnu-4.9/share/doc/as.html/Statements.html - toolchains/linux-x86/gcc - Git at Google

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 <a name="Statements"></a>
 <div class="header">
 <p>
 Next: <a href="Constants.html#Constants" accesskey="n" rel="next">Constants</a>, Previous: <a href="Symbol-Intro.html#Symbol-Intro" accesskey="p" rel="prev">Symbol Intro</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="Statements-1"></a>
 <h3 class="section">3.5 Statements</h3>

 <a name="index-statements_002c-structure-of"></a>
 <a name="index-line-separator-character"></a>
 <a name="index-statement-separator-character"></a>

 <p>A <em>statement</em> ends at a newline character (&lsquo;<samp>\n</samp>&rsquo;) or a
 <em>line separator character</em>.  The line separator character is target
 specific and described in the <em>Syntax</em> section of each
 target&rsquo;s documentation.  Not all targets support a line separator character.
 The newline or line separator character is considered to be part of the
 preceding statement.  Newlines and separators within character constants are an
 exception: they do not end statements.
 </p>
 <a name="index-newline_002c-required-at-file-end"></a>
 <a name="index-EOF_002c-newline-must-precede"></a>
 <p>It is an error to end any statement with end-of-file:  the last
 character of any input file should be a newline.
 </p>
 <p>An empty statement is allowed, and may include whitespace.  It is ignored.
 </p>
 <a name="index-instructions-and-directives"></a>
 <a name="index-directives-and-instructions"></a>
 <p>A statement begins with zero or more labels, optionally followed by a
 key symbol which determines what kind of statement it is.  The key
 symbol determines the syntax of the rest of the statement.  If the
 symbol begins with a dot &lsquo;<samp>.</samp>&rsquo; then the statement is an assembler
 directive: typically valid for any computer.  If the symbol begins with
 a letter the statement is an assembly language <em>instruction</em>: it
 assembles into a machine language instruction.
 Different versions of <code>as</code> for different computers
 recognize different instructions.  In fact, the same symbol may
 represent a different instruction in a different computer&rsquo;s assembly
 language.
 </p>
 <a name="index-_003a-_0028label_0029"></a>
 <a name="index-label-_0028_003a_0029"></a>
 <p>A label is a symbol immediately followed by a colon (<code>:</code>).
 Whitespace before a label or after a colon is permitted, but you may not
 have whitespace between a label&rsquo;s symbol and its colon. See <a href="Labels.html#Labels">Labels</a>.
 </p>
 <p>For HPPA targets, labels need not be immediately followed by a colon, but
 the definition of a label must begin in column zero.  This also implies that
 only one label may be defined on each line.
 </p>
 <div class="smallexample">
 <pre class="smallexample">label:     .directive    followed by something
 another_label:           # This is an empty statement.
            instruction   operand_1, operand_2, &hellip;
 </pre></div>

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 <p>
 Next: <a href="Constants.html#Constants" accesskey="n" rel="next">Constants</a>, Previous: <a href="Symbol-Intro.html#Symbol-Intro" accesskey="p" rel="prev">Symbol Intro</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>
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	<a name="Statements"></a>
	<div class="header">
	<p>
	Next: <a href="Constants.html#Constants" accesskey="n" rel="next">Constants</a>, Previous: <a href="Symbol-Intro.html#Symbol-Intro" accesskey="p" rel="prev">Symbol Intro</a>, Up: <a href="Syntax.html#Syntax" accesskey="u" rel="up">Syntax</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>
	</div>
	<hr>
	<a name="Statements-1"></a>
	<h3 class="section">3.5 Statements</h3>

	<a name="index-statements_002c-structure-of"></a>
	<a name="index-line-separator-character"></a>
	<a name="index-statement-separator-character"></a>

	<p>A <em>statement</em> ends at a newline character (‘<samp>\n</samp>’) or a
	<em>line separator character</em>. The line separator character is target
	specific and described in the <em>Syntax</em> section of each
	target’s documentation. Not all targets support a line separator character.
	The newline or line separator character is considered to be part of the
	preceding statement. Newlines and separators within character constants are an
	exception: they do not end statements.
	</p>
	<a name="index-newline_002c-required-at-file-end"></a>
	<a name="index-EOF_002c-newline-must-precede"></a>
	<p>It is an error to end any statement with end-of-file: the last
	character of any input file should be a newline.
	</p>
	<p>An empty statement is allowed, and may include whitespace. It is ignored.
	</p>
	<a name="index-instructions-and-directives"></a>
	<a name="index-directives-and-instructions"></a>
	<p>A statement begins with zero or more labels, optionally followed by a
	key symbol which determines what kind of statement it is. The key
	symbol determines the syntax of the rest of the statement. If the
	symbol begins with a dot ‘<samp>.</samp>’ then the statement is an assembler
	directive: typically valid for any computer. If the symbol begins with
	a letter the statement is an assembly language <em>instruction</em>: it
	assembles into a machine language instruction.
	Different versions of <code>as</code> for different computers
	recognize different instructions. In fact, the same symbol may
	represent a different instruction in a different computer’s assembly
	language.
	</p>
	<a name="index-_003a-_0028label_0029"></a>
	<a name="index-label-_0028_003a_0029"></a>
	<p>A label is a symbol immediately followed by a colon (<code>:</code>).
	Whitespace before a label or after a colon is permitted, but you may not
	have whitespace between a label’s symbol and its colon. See <a href="Labels.html#Labels">Labels</a>.
	</p>
	<p>For HPPA targets, labels need not be immediately followed by a colon, but
	the definition of a label must begin in column zero. This also implies that
	only one label may be defined on each line.
	</p>
	<div class="smallexample">
	<pre class="smallexample">label: .directive followed by something
	another_label: # This is an empty statement.
	instruction operand_1, operand_2, …
	</pre></div>

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