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95 lines
3.6 KiB
HTML
95 lines
3.6 KiB
HTML
4 years ago
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<html lang="en">
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<title>Examples - GNU Compiler Collection (GCC) Internals</title>
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<meta name="description" content="GNU Compiler Collection (GCC) Internals">
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<link title="Top" rel="start" href="index.html#Top">
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<link rel="up" href="Mode-Iterators.html#Mode-Iterators" title="Mode Iterators">
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<link rel="prev" href="Substitutions.html#Substitutions" title="Substitutions">
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<!--
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Copyright (C) 1988-2015 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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(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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</head>
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<body>
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<div class="node">
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<a name="Examples"></a>
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<p>
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Previous: <a rel="previous" accesskey="p" href="Substitutions.html#Substitutions">Substitutions</a>,
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Up: <a rel="up" accesskey="u" href="Mode-Iterators.html#Mode-Iterators">Mode Iterators</a>
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<hr>
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</div>
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<h5 class="subsubsection">16.23.1.3 Mode Iterator Examples</h5>
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<p>Here is an example from the MIPS port. It defines the following
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modes and attributes (among others):
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<pre class="smallexample"> (define_mode_iterator GPR [SI (DI "TARGET_64BIT")])
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(define_mode_attr d [(SI "") (DI "d")])
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</pre>
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<p>and uses the following template to define both <code>subsi3</code>
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and <code>subdi3</code>:
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<pre class="smallexample"> (define_insn "sub<mode>3"
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[(set (match_operand:GPR 0 "register_operand" "=d")
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(minus:GPR (match_operand:GPR 1 "register_operand" "d")
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(match_operand:GPR 2 "register_operand" "d")))]
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""
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"<d>subu\t%0,%1,%2"
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[(set_attr "type" "arith")
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(set_attr "mode" "<MODE>")])
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</pre>
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<p>This is exactly equivalent to:
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<pre class="smallexample"> (define_insn "subsi3"
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[(set (match_operand:SI 0 "register_operand" "=d")
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(minus:SI (match_operand:SI 1 "register_operand" "d")
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(match_operand:SI 2 "register_operand" "d")))]
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""
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"subu\t%0,%1,%2"
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[(set_attr "type" "arith")
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(set_attr "mode" "SI")])
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(define_insn "subdi3"
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[(set (match_operand:DI 0 "register_operand" "=d")
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(minus:DI (match_operand:DI 1 "register_operand" "d")
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(match_operand:DI 2 "register_operand" "d")))]
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""
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"dsubu\t%0,%1,%2"
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[(set_attr "type" "arith")
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(set_attr "mode" "DI")])
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</pre>
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</body></html>
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