diff options
| author | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
|---|---|---|
| committer | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
| commit | abdaadbcae30fe0c9a66c7516798279fdfd97750 (patch) | |
| tree | 00a54a6e25601e43876d03c1a4a12a749d4a914c /share/doc/gccint/Constraints.html | |
https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads
Change-Id: I7303388733328cd98ab9aa3c30236db67f2e9e9c
Diffstat (limited to 'share/doc/gccint/Constraints.html')
| -rw-r--r-- | share/doc/gccint/Constraints.html | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/share/doc/gccint/Constraints.html b/share/doc/gccint/Constraints.html new file mode 100644 index 0000000..bb20030 --- /dev/null +++ b/share/doc/gccint/Constraints.html @@ -0,0 +1,121 @@ +<!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: Constraints</title> + +<meta name="description" content="GNU Compiler Collection (GCC) Internals: Constraints"> +<meta name="keywords" content="GNU Compiler Collection (GCC) Internals: Constraints"> +<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="Simple-Constraints.html#Simple-Constraints" rel="next" title="Simple Constraints"> +<link href="Defining-Predicates.html#Defining-Predicates" rel="previous" title="Defining Predicates"> +<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="Constraints"></a> +<div class="header"> +<p> +Next: <a href="Standard-Names.html#Standard-Names" accesskey="n" rel="next">Standard Names</a>, Previous: <a href="Predicates.html#Predicates" accesskey="p" rel="previous">Predicates</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="Operand-Constraints"></a> +<h3 class="section">17.8 Operand Constraints</h3> +<a name="index-operand-constraints"></a> +<a name="index-constraints"></a> + +<p>Each <code>match_operand</code> in an instruction pattern can specify +constraints for the operands allowed. The constraints allow you to +fine-tune matching within the set of operands allowed by the +predicate. +</p> +<p>Constraints can say whether +an operand may be in a register, and which kinds of register; whether the +operand can be a memory reference, and which kinds of address; whether the +operand may be an immediate constant, and which possible values it may +have. Constraints can also require two operands to match. +Side-effects aren’t allowed in operands of inline <code>asm</code>, unless +‘<samp><</samp>’ or ‘<samp>></samp>’ constraints are used, because there is no guarantee +that the side effects will happen exactly once in an instruction that can update +the addressing register. +</p> +<table class="menu" border="0" cellspacing="0"> +<tr><td align="left" valign="top">• <a href="Simple-Constraints.html#Simple-Constraints" accesskey="1">Simple Constraints</a>:</td><td> </td><td align="left" valign="top">Basic use of constraints. +</td></tr> +<tr><td align="left" valign="top">• <a href="Multi_002dAlternative.html#Multi_002dAlternative" accesskey="2">Multi-Alternative</a>:</td><td> </td><td align="left" valign="top">When an insn has two alternative constraint-patterns. +</td></tr> +<tr><td align="left" valign="top">• <a href="Class-Preferences.html#Class-Preferences" accesskey="3">Class Preferences</a>:</td><td> </td><td align="left" valign="top">Constraints guide which hard register to put things in. +</td></tr> +<tr><td align="left" valign="top">• <a href="Modifiers.html#Modifiers" accesskey="4">Modifiers</a>:</td><td> </td><td align="left" valign="top">More precise control over effects of constraints. +</td></tr> +<tr><td align="left" valign="top">• <a href="Machine-Constraints.html#Machine-Constraints" accesskey="5">Machine Constraints</a>:</td><td> </td><td align="left" valign="top">Existing constraints for some particular machines. +</td></tr> +<tr><td align="left" valign="top">• <a href="Disable-Insn-Alternatives.html#Disable-Insn-Alternatives" accesskey="6">Disable Insn Alternatives</a>:</td><td> </td><td align="left" valign="top">Disable insn alternatives using attributes. +</td></tr> +<tr><td align="left" valign="top">• <a href="Define-Constraints.html#Define-Constraints" accesskey="7">Define Constraints</a>:</td><td> </td><td align="left" valign="top">How to define machine-specific constraints. +</td></tr> +<tr><td align="left" valign="top">• <a href="C-Constraint-Interface.html#C-Constraint-Interface" accesskey="8">C Constraint Interface</a>:</td><td> </td><td align="left" valign="top">How to test constraints from C code. +</td></tr> +</table> + + + + + +</body> +</html> |