121 lines
5.2 KiB
HTML
121 lines
5.2 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<!-- Copyright (C) 1988-2016 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 or
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any later version published by the Free Software Foundation; with the
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Invariant Sections being "Funding Free Software", the Front-Cover
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Texts being (a) (see below), and with the Back-Cover Texts being (b)
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(see below). A copy of the license is included in the section entitled
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"GNU Free Documentation License".
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(a) The FSF's Front-Cover Text is:
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A GNU Manual
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(b) The FSF's Back-Cover Text is:
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You have freedom to copy and modify this GNU Manual, like GNU
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software. Copies published by the Free Software Foundation raise
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funds for GNU development. -->
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<!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ -->
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<head>
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<title>GNU Compiler Collection (GCC) Internals: Mnemonic Attribute</title>
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<meta name="description" content="GNU Compiler Collection (GCC) Internals: Mnemonic Attribute">
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<meta name="keywords" content="GNU Compiler Collection (GCC) Internals: Mnemonic Attribute">
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<link href="index.html#Top" rel="start" title="Top">
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<link href="Option-Index.html#Option-Index" rel="index" title="Option Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="Insn-Attributes.html#Insn-Attributes" rel="up" title="Insn Attributes">
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<link href="Delay-Slots.html#Delay-Slots" rel="next" title="Delay Slots">
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<link href="Constant-Attributes.html#Constant-Attributes" rel="prev" title="Constant Attributes">
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</head>
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<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
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<a name="Mnemonic-Attribute"></a>
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<div class="header">
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<p>
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Next: <a href="Delay-Slots.html#Delay-Slots" accesskey="n" rel="next">Delay Slots</a>, Previous: <a href="Constant-Attributes.html#Constant-Attributes" accesskey="p" rel="prev">Constant Attributes</a>, Up: <a href="Insn-Attributes.html#Insn-Attributes" accesskey="u" rel="up">Insn Attributes</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<a name="Mnemonic-Attribute-1"></a>
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<h4 class="subsection">16.19.7 Mnemonic Attribute</h4>
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<a name="index-mnemonic-attribute"></a>
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<p>The <code>mnemonic</code> attribute is a string type attribute holding the
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instruction mnemonic for an insn alternative. The attribute values
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will automatically be generated by the machine description parser if
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there is an attribute definition in the md file:
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</p>
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<div class="smallexample">
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<pre class="smallexample">(define_attr "mnemonic" "unknown" (const_string "unknown"))
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</pre></div>
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<p>The default value can be freely chosen as long as it does not collide
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with any of the instruction mnemonics. This value will be used
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whenever the machine description parser is not able to determine the
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mnemonic string. This might be the case for output templates
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containing more than a single instruction as in
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<code>"mvcle\t%0,%1,0\;jo\t.-4"</code>.
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</p>
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<p>The <code>mnemonic</code> attribute set is not generated automatically if the
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instruction string is generated via C code.
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</p>
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<p>An existing <code>mnemonic</code> attribute set in an insn definition will not
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be overriden by the md file parser. That way it is possible to
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manually set the instruction mnemonics for the cases where the md file
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parser fails to determine it automatically.
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</p>
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<p>The <code>mnemonic</code> attribute is useful for dealing with instruction
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specific properties in the pipeline description without defining
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additional insn attributes.
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</p>
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<div class="smallexample">
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<pre class="smallexample">(define_attr "ooo_expanded" ""
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(cond [(eq_attr "mnemonic" "dlr,dsgr,d,dsgf,stam,dsgfr,dlgr")
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(const_int 1)]
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(const_int 0)))
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</pre></div>
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</body>
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</html>
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