<html lang="en"> <head> <title>Expressions - 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="prev" href="Symbols.html#Symbols" title="Symbols"> <link rel="next" href="Pseudo-Ops.html#Pseudo-Ops" title="Pseudo Ops"> <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> <!-- This file documents the GNU Assembler "as". Copyright (C) 1991-2015 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="Expressions"></a> <p> Next: <a rel="next" accesskey="n" href="Pseudo-Ops.html#Pseudo-Ops">Pseudo Ops</a>, Previous: <a rel="previous" accesskey="p" href="Symbols.html#Symbols">Symbols</a>, Up: <a rel="up" accesskey="u" href="index.html#Top">Top</a> <hr> </div> <h2 class="chapter">6 Expressions</h2> <p><a name="index-expressions-241"></a><a name="index-addresses-242"></a><a name="index-numeric-values-243"></a>An <dfn>expression</dfn> specifies an address or numeric value. Whitespace may precede and/or follow an expression. <p>The result of an expression must be an absolute number, or else an offset into a particular section. If an expression is not absolute, and there is not enough information when <samp><span class="command">as</span></samp> sees the expression to know its section, a second pass over the source program might be necessary to interpret the expression—but the second pass is currently not implemented. <samp><span class="command">as</span></samp> aborts with an error message in this situation. <ul class="menu"> <li><a accesskey="1" href="Empty-Exprs.html#Empty-Exprs">Empty Exprs</a>: Empty Expressions <li><a accesskey="2" href="Integer-Exprs.html#Integer-Exprs">Integer Exprs</a>: Integer Expressions </ul> </body></html>