| <html lang="en"> |
| <head> |
| <title>Statements - 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="Syntax.html#Syntax" title="Syntax"> |
| <link rel="prev" href="Symbol-Intro.html#Symbol-Intro" title="Symbol Intro"> |
| <link rel="next" href="Constants.html#Constants" title="Constants"> |
| <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="Statements"></a> |
| <p> |
| Next: <a rel="next" accesskey="n" href="Constants.html#Constants">Constants</a>, |
| Previous: <a rel="previous" accesskey="p" href="Symbol-Intro.html#Symbol-Intro">Symbol Intro</a>, |
| Up: <a rel="up" accesskey="u" href="Syntax.html#Syntax">Syntax</a> |
| <hr> |
| </div> |
| |
| <h3 class="section">3.5 Statements</h3> |
| |
| <p><a name="index-statements_002c-structure-of-132"></a><a name="index-line-separator-character-133"></a><a name="index-statement-separator-character-134"></a> |
| A <dfn>statement</dfn> ends at a newline character (‘<samp><span class="samp">\n</span></samp>’) or a |
| <dfn>line separator character</dfn>. 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-135"></a><a name="index-EOF_002c-newline-must-precede-136"></a>It is an error to end any statement with end-of-file: the last |
| character of any input file should be a newline. |
| |
| <p>An empty statement is allowed, and may include whitespace. It is ignored. |
| |
| <p><a name="index-instructions-and-directives-137"></a><a name="index-directives-and-instructions-138"></a><!-- "key symbol" is not used elsewhere in the document; seems pedantic to --> |
| <!-- @defn{} it in that case, as was done previously... doc@cygnus.com, --> |
| <!-- 13feb91. --> |
| 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><span class="samp">.</span></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 <dfn>instruction</dfn>: it |
| assembles into a machine language instruction. |
| Different versions of <samp><span class="command">as</span></samp> 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-g_t_0040code_007b_003a_007d-_0028label_0029-139"></a><a name="index-label-_0028_0040code_007b_003a_007d_0029-140"></a>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>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. |
| |
| <pre class="smallexample"> label: .directive followed by something |
| another_label: # This is an empty statement. |
| instruction operand_1, operand_2, ... |
| </pre> |
| </body></html> |
| |
