diff options
Diffstat (limited to 'share/doc/gccint/Alignment-Output.html')
| -rw-r--r-- | share/doc/gccint/Alignment-Output.html | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/share/doc/gccint/Alignment-Output.html b/share/doc/gccint/Alignment-Output.html new file mode 100644 index 0000000..c1c527c --- /dev/null +++ b/share/doc/gccint/Alignment-Output.html @@ -0,0 +1,182 @@ +<!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: Alignment Output</title> + +<meta name="description" content="GNU Compiler Collection (GCC) Internals: Alignment Output"> +<meta name="keywords" content="GNU Compiler Collection (GCC) Internals: Alignment Output"> +<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="Assembler-Format.html#Assembler-Format" rel="up" title="Assembler Format"> +<link href="Debugging-Info.html#Debugging-Info" rel="next" title="Debugging Info"> +<link href="Exception-Region-Output.html#Exception-Region-Output" rel="previous" title="Exception Region Output"> +<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="Alignment-Output"></a> +<div class="header"> +<p> +Previous: <a href="Exception-Region-Output.html#Exception-Region-Output" accesskey="p" rel="previous">Exception Region Output</a>, Up: <a href="Assembler-Format.html#Assembler-Format" accesskey="u" rel="up">Assembler Format</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="Assembler-Commands-for-Alignment"></a> +<h4 class="subsection">18.20.10 Assembler Commands for Alignment</h4> + +<p>This describes commands for alignment. +</p> +<dl> +<dt><a name="index-JUMP_005fALIGN"></a>Macro: <strong>JUMP_ALIGN</strong> <em>(<var>label</var>)</em></dt> +<dd><p>The alignment (log base 2) to put in front of <var>label</var>, which is +a common destination of jumps and has no fallthru incoming edge. +</p> +<p>This macro need not be defined if you don’t want any special alignment +to be done at such a time. Most machine descriptions do not currently +define the macro. +</p> +<p>Unless it’s necessary to inspect the <var>label</var> parameter, it is better +to set the variable <var>align_jumps</var> in the target’s +<code>TARGET_OPTION_OVERRIDE</code>. Otherwise, you should try to honor the user’s +selection in <var>align_jumps</var> in a <code>JUMP_ALIGN</code> implementation. +</p></dd></dl> + +<dl> +<dt><a name="index-LABEL_005fALIGN_005fAFTER_005fBARRIER"></a>Macro: <strong>LABEL_ALIGN_AFTER_BARRIER</strong> <em>(<var>label</var>)</em></dt> +<dd><p>The alignment (log base 2) to put in front of <var>label</var>, which follows +a <code>BARRIER</code>. +</p> +<p>This macro need not be defined if you don’t want any special alignment +to be done at such a time. Most machine descriptions do not currently +define the macro. +</p></dd></dl> + +<dl> +<dt><a name="index-LOOP_005fALIGN"></a>Macro: <strong>LOOP_ALIGN</strong> <em>(<var>label</var>)</em></dt> +<dd><p>The alignment (log base 2) to put in front of <var>label</var> that heads +a frequently executed basic block (usually the header of a loop). +</p> +<p>This macro need not be defined if you don’t want any special alignment +to be done at such a time. Most machine descriptions do not currently +define the macro. +</p> +<p>Unless it’s necessary to inspect the <var>label</var> parameter, it is better +to set the variable <code>align_loops</code> in the target’s +<code>TARGET_OPTION_OVERRIDE</code>. Otherwise, you should try to honor the user’s +selection in <code>align_loops</code> in a <code>LOOP_ALIGN</code> implementation. +</p></dd></dl> + +<dl> +<dt><a name="index-LABEL_005fALIGN"></a>Macro: <strong>LABEL_ALIGN</strong> <em>(<var>label</var>)</em></dt> +<dd><p>The alignment (log base 2) to put in front of <var>label</var>. +If <code>LABEL_ALIGN_AFTER_BARRIER</code> / <code>LOOP_ALIGN</code> specify a different alignment, +the maximum of the specified values is used. +</p> +<p>Unless it’s necessary to inspect the <var>label</var> parameter, it is better +to set the variable <code>align_labels</code> in the target’s +<code>TARGET_OPTION_OVERRIDE</code>. Otherwise, you should try to honor the user’s +selection in <code>align_labels</code> in a <code>LABEL_ALIGN</code> implementation. +</p></dd></dl> + +<dl> +<dt><a name="index-ASM_005fOUTPUT_005fSKIP"></a>Macro: <strong>ASM_OUTPUT_SKIP</strong> <em>(<var>stream</var>, <var>nbytes</var>)</em></dt> +<dd><p>A C statement to output to the stdio stream <var>stream</var> an assembler +instruction to advance the location counter by <var>nbytes</var> bytes. +Those bytes should be zero when loaded. <var>nbytes</var> will be a C +expression of type <code>unsigned HOST_WIDE_INT</code>. +</p></dd></dl> + +<dl> +<dt><a name="index-ASM_005fNO_005fSKIP_005fIN_005fTEXT"></a>Macro: <strong>ASM_NO_SKIP_IN_TEXT</strong></dt> +<dd><p>Define this macro if <code>ASM_OUTPUT_SKIP</code> should not be used in the +text section because it fails to put zeros in the bytes that are skipped. +This is true on many Unix systems, where the pseudo–op to skip bytes +produces no-op instructions rather than zeros when used in the text +section. +</p></dd></dl> + +<dl> +<dt><a name="index-ASM_005fOUTPUT_005fALIGN"></a>Macro: <strong>ASM_OUTPUT_ALIGN</strong> <em>(<var>stream</var>, <var>power</var>)</em></dt> +<dd><p>A C statement to output to the stdio stream <var>stream</var> an assembler +command to advance the location counter to a multiple of 2 to the +<var>power</var> bytes. <var>power</var> will be a C expression of type <code>int</code>. +</p></dd></dl> + +<dl> +<dt><a name="index-ASM_005fOUTPUT_005fALIGN_005fWITH_005fNOP"></a>Macro: <strong>ASM_OUTPUT_ALIGN_WITH_NOP</strong> <em>(<var>stream</var>, <var>power</var>)</em></dt> +<dd><p>Like <code>ASM_OUTPUT_ALIGN</code>, except that the “nop” instruction is used +for padding, if necessary. +</p></dd></dl> + +<dl> +<dt><a name="index-ASM_005fOUTPUT_005fMAX_005fSKIP_005fALIGN"></a>Macro: <strong>ASM_OUTPUT_MAX_SKIP_ALIGN</strong> <em>(<var>stream</var>, <var>power</var>, <var>max_skip</var>)</em></dt> +<dd><p>A C statement to output to the stdio stream <var>stream</var> an assembler +command to advance the location counter to a multiple of 2 to the +<var>power</var> bytes, but only if <var>max_skip</var> or fewer bytes are needed to +satisfy the alignment request. <var>power</var> and <var>max_skip</var> will be +a C expression of type <code>int</code>. +</p></dd></dl> + +<hr> +<div class="header"> +<p> +Previous: <a href="Exception-Region-Output.html#Exception-Region-Output" accesskey="p" rel="previous">Exception Region Output</a>, Up: <a href="Assembler-Format.html#Assembler-Format" accesskey="u" rel="up">Assembler Format</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> |