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diff --git a/share/doc/gccint/Example.html b/share/doc/gccint/Example.html new file mode 100644 index 0000000..0ed7d81 --- /dev/null +++ b/share/doc/gccint/Example.html @@ -0,0 +1,128 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- Copyright (C) 1988-2023 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 the +Invariant Sections being "Funding Free Software", the Front-Cover +Texts being (a) (see below), and with the Back-Cover Texts being (b) +(see below). A copy of the license is included in the section entitled +"GNU Free Documentation License". + +(a) The FSF's Front-Cover Text is: + +A GNU Manual + +(b) The FSF's Back-Cover Text is: + +You have freedom to copy and modify this GNU Manual, like GNU + software. Copies published by the Free Software Foundation raise + funds for GNU development. --> +<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ --> +<head> +<title>GNU Compiler Collection (GCC) Internals: Example</title> + +<meta name="description" content="GNU Compiler Collection (GCC) Internals: Example"> +<meta name="keywords" content="GNU Compiler Collection (GCC) Internals: Example"> +<meta name="resource-type" content="document"> +<meta name="distribution" content="global"> +<meta name="Generator" content="makeinfo"> +<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> +<link href="index.html#Top" rel="start" title="Top"> +<link href="Option-Index.html#Option-Index" rel="index" title="Option Index"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="Machine-Desc.html#Machine-Desc" rel="up" title="Machine Desc"> +<link href="RTL-Template.html#RTL-Template" rel="next" title="RTL Template"> +<link href="Patterns.html#Patterns" rel="previous" title="Patterns"> +<style type="text/css"> +<!-- +a.summary-letter {text-decoration: none} +blockquote.smallquotation {font-size: smaller} +div.display {margin-left: 3.2em} +div.example {margin-left: 3.2em} +div.indentedblock {margin-left: 3.2em} +div.lisp {margin-left: 3.2em} +div.smalldisplay {margin-left: 3.2em} +div.smallexample {margin-left: 3.2em} +div.smallindentedblock {margin-left: 3.2em; font-size: smaller} +div.smalllisp {margin-left: 3.2em} +kbd {font-style:oblique} +pre.display {font-family: inherit} +pre.format {font-family: inherit} +pre.menu-comment {font-family: serif} +pre.menu-preformatted {font-family: serif} +pre.smalldisplay {font-family: inherit; font-size: smaller} +pre.smallexample {font-size: smaller} +pre.smallformat {font-family: inherit; font-size: smaller} +pre.smalllisp {font-size: smaller} +span.nocodebreak {white-space:nowrap} +span.nolinebreak {white-space:nowrap} +span.roman {font-family:serif; font-weight:normal} +span.sansserif {font-family:sans-serif; font-weight:normal} +ul.no-bullet {list-style: none} +--> +</style> + + +</head> + +<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> +<a name="Example"></a> +<div class="header"> +<p> +Next: <a href="RTL-Template.html#RTL-Template" accesskey="n" rel="next">RTL Template</a>, Previous: <a href="Patterns.html#Patterns" accesskey="p" rel="previous">Patterns</a>, Up: <a href="Machine-Desc.html#Machine-Desc" accesskey="u" rel="up">Machine Desc</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> +</div> +<hr> +<a name="Example-of-define_005finsn"></a> +<h3 class="section">17.3 Example of <code>define_insn</code></h3> +<a name="index-define_005finsn-example"></a> + +<p>Here is an example of an instruction pattern, taken from the machine +description for the 68000/68020. +</p> +<div class="smallexample"> +<pre class="smallexample">(define_insn "tstsi" + [(set (cc0) + (match_operand:SI 0 "general_operand" "rm"))] + "" + "* +{ + if (TARGET_68020 || ! ADDRESS_REG_P (operands[0])) + return \"tstl %0\"; + return \"cmpl #0,%0\"; +}") +</pre></div> + +<p>This can also be written using braced strings: +</p> +<div class="smallexample"> +<pre class="smallexample">(define_insn "tstsi" + [(set (cc0) + (match_operand:SI 0 "general_operand" "rm"))] + "" +{ + if (TARGET_68020 || ! ADDRESS_REG_P (operands[0])) + return "tstl %0"; + return "cmpl #0,%0"; +}) +</pre></div> + +<p>This describes an instruction which sets the condition codes based on the +value of a general operand. It has no condition, so any insn with an RTL +description of the form shown may be matched to this pattern. The name +‘<samp>tstsi</samp>’ means “test a <code>SImode</code> value” and tells the RTL +generation pass that, when it is necessary to test such a value, an insn +to do so can be constructed using this pattern. +</p> +<p>The output control string is a piece of C code which chooses which +output template to return based on the kind of operand and the specific +type of CPU for which code is being generated. +</p> +<p>‘<samp>"rm"</samp>’ is an operand constraint. Its meaning is explained below. +</p> + + + +</body> +</html> |