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diff --git a/share/doc/gccint/Output-Template.html b/share/doc/gccint/Output-Template.html new file mode 100644 index 0000000..8bc1030 --- /dev/null +++ b/share/doc/gccint/Output-Template.html @@ -0,0 +1,179 @@ +<!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: Output Template</title> + +<meta name="description" content="GNU Compiler Collection (GCC) Internals: Output Template"> +<meta name="keywords" content="GNU Compiler Collection (GCC) Internals: Output Template"> +<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="Output-Statement.html#Output-Statement" rel="next" title="Output Statement"> +<link href="RTL-Template.html#RTL-Template" rel="previous" title="RTL Template"> +<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="Output-Template"></a> +<div class="header"> +<p> +Next: <a href="Output-Statement.html#Output-Statement" accesskey="n" rel="next">Output Statement</a>, Previous: <a href="RTL-Template.html#RTL-Template" accesskey="p" rel="previous">RTL Template</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="Output-Templates-and-Operand-Substitution"></a> +<h3 class="section">17.5 Output Templates and Operand Substitution</h3> +<a name="index-output-templates"></a> +<a name="index-operand-substitution"></a> + +<a name="index-_0025-in-template"></a> +<a name="index-percent-sign"></a> +<p>The <em>output template</em> is a string which specifies how to output the +assembler code for an instruction pattern. Most of the template is a +fixed string which is output literally. The character ‘<samp>%</samp>’ is used +to specify where to substitute an operand; it can also be used to +identify places where different variants of the assembler require +different syntax. +</p> +<p>In the simplest case, a ‘<samp>%</samp>’ followed by a digit <var>n</var> says to output +operand <var>n</var> at that point in the string. +</p> +<p>‘<samp>%</samp>’ followed by a letter and a digit says to output an operand in an +alternate fashion. Four letters have standard, built-in meanings described +below. The machine description macro <code>PRINT_OPERAND</code> can define +additional letters with nonstandard meanings. +</p> +<p>‘<samp>%c<var>digit</var></samp>’ can be used to substitute an operand that is a +constant value without the syntax that normally indicates an immediate +operand. +</p> +<p>‘<samp>%n<var>digit</var></samp>’ is like ‘<samp>%c<var>digit</var></samp>’ except that the value of +the constant is negated before printing. +</p> +<p>‘<samp>%a<var>digit</var></samp>’ can be used to substitute an operand as if it were a +memory reference, with the actual operand treated as the address. This may +be useful when outputting a “load address” instruction, because often the +assembler syntax for such an instruction requires you to write the operand +as if it were a memory reference. +</p> +<p>‘<samp>%l<var>digit</var></samp>’ is used to substitute a <code>label_ref</code> into a jump +instruction. +</p> +<p>‘<samp>%=</samp>’ outputs a number which is unique to each instruction in the +entire compilation. This is useful for making local labels to be +referred to more than once in a single template that generates multiple +assembler instructions. +</p> +<p>‘<samp>%</samp>’ followed by a punctuation character specifies a substitution that +does not use an operand. Only one case is standard: ‘<samp>%%</samp>’ outputs a +‘<samp>%</samp>’ into the assembler code. Other nonstandard cases can be +defined in the <code>PRINT_OPERAND</code> macro. You must also define +which punctuation characters are valid with the +<code>PRINT_OPERAND_PUNCT_VALID_P</code> macro. +</p> +<a name="index-_005c"></a> +<a name="index-backslash"></a> +<p>The template may generate multiple assembler instructions. Write the text +for the instructions, with ‘<samp>\;</samp>’ between them. +</p> +<a name="index-matching-operands"></a> +<p>When the RTL contains two operands which are required by constraint to match +each other, the output template must refer only to the lower-numbered operand. +Matching operands are not always identical, and the rest of the compiler +arranges to put the proper RTL expression for printing into the lower-numbered +operand. +</p> +<p>One use of nonstandard letters or punctuation following ‘<samp>%</samp>’ is to +distinguish between different assembler languages for the same machine; for +example, Motorola syntax versus MIT syntax for the 68000. Motorola syntax +requires periods in most opcode names, while MIT syntax does not. For +example, the opcode ‘<samp>movel</samp>’ in MIT syntax is ‘<samp>move.l</samp>’ in Motorola +syntax. The same file of patterns is used for both kinds of output syntax, +but the character sequence ‘<samp>%.</samp>’ is used in each place where Motorola +syntax wants a period. The <code>PRINT_OPERAND</code> macro for Motorola syntax +defines the sequence to output a period; the macro for MIT syntax defines +it to do nothing. +</p> +<a name="index-_0023-in-template"></a> +<p>As a special case, a template consisting of the single character <code>#</code> +instructs the compiler to first split the insn, and then output the +resulting instructions separately. This helps eliminate redundancy in the +output templates. If you have a <code>define_insn</code> that needs to emit +multiple assembler instructions, and there is a matching <code>define_split</code> +already defined, then you can simply use <code>#</code> as the output template +instead of writing an output template that emits the multiple assembler +instructions. +</p> +<p>Note that <code>#</code> only has an effect while generating assembly code; +it does not affect whether a split occurs earlier. An associated +<code>define_split</code> must exist and it must be suitable for use after +register allocation. +</p> +<p>If the macro <code>ASSEMBLER_DIALECT</code> is defined, you can use construct +of the form ‘<samp>{option0|option1|option2}</samp>’ in the templates. These +describe multiple variants of assembler language syntax. +See <a href="Instruction-Output.html#Instruction-Output">Instruction Output</a>. +</p> +<hr> +<div class="header"> +<p> +Next: <a href="Output-Statement.html#Output-Statement" accesskey="n" rel="next">Output Statement</a>, Previous: <a href="RTL-Template.html#RTL-Template" accesskey="p" rel="previous">RTL Template</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> + + + +</body> +</html> |