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129 lines
5.4 KiB
HTML
129 lines
5.4 KiB
HTML
15 years ago
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<html lang="en">
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<head>
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<title>Infix Ops - 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 4.7">
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<link title="Top" rel="start" href="index.html#Top">
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<link rel="up" href="Integer-Exprs.html#Integer-Exprs" title="Integer Exprs">
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<link rel="prev" href="Prefix-Ops.html#Prefix-Ops" title="Prefix Ops">
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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, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001, 2002,
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2006, 2007 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 1.1
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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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man end-->
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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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--></style>
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</head>
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<body>
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<div class="node">
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<p>
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<a name="Infix-Ops"></a>Previous: <a rel="previous" accesskey="p" href="Prefix-Ops.html#Prefix-Ops">Prefix Ops</a>,
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Up: <a rel="up" accesskey="u" href="Integer-Exprs.html#Integer-Exprs">Integer Exprs</a>
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<hr><br>
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</div>
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<h4 class="subsection">6.2.4 Infix Operators</h4>
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<p><a name="index-infix-operators-257"></a><a name="index-operators_002c-permitted-arguments-258"></a><dfn>Infix operators</dfn> take two arguments, one on either side. Operators
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have precedence, but operations with equal precedence are performed left
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to right. Apart from <code>+</code> or <span class="option">-</span>, both arguments must be
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absolute, and the result is absolute.
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<ol type=1 start=1>
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<a name="index-operator-precedence-259"></a><a name="index-precedence-of-operators-260"></a>
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<li>Highest Precedence
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<dl>
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<dt><code>*</code><dd><dfn>Multiplication</dfn>.
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<br><dt><code>/</code><dd><dfn>Division</dfn>. Truncation is the same as the C operator <span class="samp">/</span>
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<br><dt><code>%</code><dd><dfn>Remainder</dfn>.
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<br><dt><code><<</code><dd><dfn>Shift Left</dfn>. Same as the C operator <span class="samp"><<</span>.
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<br><dt><code>>></code><dd><dfn>Shift Right</dfn>. Same as the C operator <span class="samp">>></span>.
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</dl>
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<li>Intermediate precedence
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<dl>
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<dt><code>|</code><dd>
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<dfn>Bitwise Inclusive Or</dfn>.
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<br><dt><code>&</code><dd><dfn>Bitwise And</dfn>.
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<br><dt><code>^</code><dd><dfn>Bitwise Exclusive Or</dfn>.
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<br><dt><code>!</code><dd><dfn>Bitwise Or Not</dfn>.
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</dl>
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<li>Low Precedence
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<a name="index-addition_002c-permitted-arguments-261"></a>
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<a name="index-plus_002c-permitted-arguments-262"></a>
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<a name="index-arguments-for-addition-263"></a>
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<dl><dt><code>+</code><dd><dfn>Addition</dfn>. If either argument is absolute, the result has the section of
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the other argument. You may not add together arguments from different
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sections.
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<p><a name="index-subtraction_002c-permitted-arguments-264"></a><a name="index-minus_002c-permitted-arguments-265"></a><a name="index-arguments-for-subtraction-266"></a><br><dt><code>-</code><dd><dfn>Subtraction</dfn>. If the right argument is absolute, the
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result has the section of the left argument.
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If both arguments are in the same section, the result is absolute.
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You may not subtract arguments from different sections.
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<!-- FIXME is there still something useful to say about undefined - undefined ? -->
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<p><a name="index-comparison-expressions-267"></a><a name="index-expressions_002c-comparison-268"></a><br><dt><code>==</code><dd><dfn>Is Equal To</dfn>
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<br><dt><code><></code><dt><code>!=</code><dd><dfn>Is Not Equal To</dfn>
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<br><dt><code><</code><dd><dfn>Is Less Than</dfn>
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<br><dt><code>></code><dd><dfn>Is Greater Than</dfn>
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<br><dt><code>>=</code><dd><dfn>Is Greater Than Or Equal To</dfn>
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<br><dt><code><=</code><dd><dfn>Is Less Than Or Equal To</dfn>
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<p>The comparison operators can be used as infix operators. A true results has a
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value of -1 whereas a false result has a value of 0. Note, these operators
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perform signed comparisons.
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</dl>
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<li>Lowest Precedence
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<dl>
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<dt><code>&&</code><dd><dfn>Logical And</dfn>.
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<br><dt><code>||</code><dd><dfn>Logical Or</dfn>.
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<p>These two logical operations can be used to combine the results of sub
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expressions. Note, unlike the comparison operators a true result returns a
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value of 1 but a false results does still return 0. Also note that the logical
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or operator has a slightly lower precedence than logical and.
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</dl>
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</ol>
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<p>In short, it's only meaningful to add or subtract the <em>offsets</em> in an
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address; you can only have a defined section in one of the two arguments.
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</body></html>
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