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diff --git a/share/doc/gccint/Alignment-of-poly_005fints.html b/share/doc/gccint/Alignment-of-poly_005fints.html new file mode 100644 index 0000000..c3ad140 --- /dev/null +++ b/share/doc/gccint/Alignment-of-poly_005fints.html @@ -0,0 +1,180 @@ +<!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 of poly_ints</title> + +<meta name="description" content="GNU Compiler Collection (GCC) Internals: Alignment of poly_ints"> +<meta name="keywords" content="GNU Compiler Collection (GCC) Internals: Alignment of poly_ints"> +<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="poly_005fint.html#poly_005fint" rel="up" title="poly_int"> +<link href="Computing-bounds-on-poly_005fints.html#Computing-bounds-on-poly_005fints" rel="next" title="Computing bounds on poly_ints"> +<link href="Other-poly_005fint-arithmetic.html#Other-poly_005fint-arithmetic" rel="previous" title="Other poly_int arithmetic"> +<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-of-poly_005fints"></a> +<div class="header"> +<p> +Next: <a href="Computing-bounds-on-poly_005fints.html#Computing-bounds-on-poly_005fints" accesskey="n" rel="next">Computing bounds on <code>poly_int</code>s</a>, Previous: <a href="Arithmetic-on-poly_005fints.html#Arithmetic-on-poly_005fints" accesskey="p" rel="previous">Arithmetic on <code>poly_int</code>s</a>, Up: <a href="poly_005fint.html#poly_005fint" accesskey="u" rel="up">poly_int</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="Alignment-of-poly_005fints-1"></a> +<h3 class="section">10.5 Alignment of <code>poly_int</code>s</h3> + +<p><code>poly_int</code> provides various routines for aligning values and for querying +misalignments. In each case the alignment must be a power of 2. +</p> +<dl compact="compact"> +<dt>‘<samp>can_align_p (<var>value</var>, <var>align</var>)</samp>’</dt> +<dd><p>Return true if we can align <var>value</var> up or down to the nearest multiple +of <var>align</var> at compile time. The answer is the same for both directions. +</p> +</dd> +<dt>‘<samp>can_align_down (<var>value</var>, <var>align</var>, &<var>aligned</var>)</samp>’</dt> +<dd><p>Return true if <code>can_align_p</code>; if so, set <var>aligned</var> to the greatest +aligned value that is less than or equal to <var>value</var>. +</p> +</dd> +<dt>‘<samp>can_align_up (<var>value</var>, <var>align</var>, &<var>aligned</var>)</samp>’</dt> +<dd><p>Return true if <code>can_align_p</code>; if so, set <var>aligned</var> to the lowest +aligned value that is greater than or equal to <var>value</var>. +</p> +</dd> +<dt>‘<samp>known_equal_after_align_down (<var>a</var>, <var>b</var>, <var>align</var>)</samp>’</dt> +<dd><p>Return true if we can align <var>a</var> and <var>b</var> down to the nearest +<var>align</var> boundary at compile time and if the two results are equal. +</p> +</dd> +<dt>‘<samp>known_equal_after_align_up (<var>a</var>, <var>b</var>, <var>align</var>)</samp>’</dt> +<dd><p>Return true if we can align <var>a</var> and <var>b</var> up to the nearest +<var>align</var> boundary at compile time and if the two results are equal. +</p> +</dd> +<dt>‘<samp>aligned_lower_bound (<var>value</var>, <var>align</var>)</samp>’</dt> +<dd><p>Return a result that is no greater than <var>value</var> and that is aligned +to <var>align</var>. The result will the closest aligned value for some +indeterminate values but not necessarily for all. +</p> +<p>For example, suppose we are allocating an object of <var>size</var> bytes +in a downward-growing stack whose current limit is given by <var>limit</var>. +If the object requires <var>align</var> bytes of alignment, the new stack +limit is given by: +</p> +<div class="smallexample"> +<pre class="smallexample">aligned_lower_bound (<var>limit</var> - <var>size</var>, <var>align</var>) +</pre></div> + +</dd> +<dt>‘<samp>aligned_upper_bound (<var>value</var>, <var>align</var>)</samp>’</dt> +<dd><p>Likewise return a result that is no less than <var>value</var> and that is +aligned to <var>align</var>. This is the routine that would be used for +upward-growing stacks in the scenario just described. +</p> +</dd> +<dt>‘<samp>known_misalignment (<var>value</var>, <var>align</var>, &<var>misalign</var>)</samp>’</dt> +<dd><p>Return true if we can calculate the misalignment of <var>value</var> +with respect to <var>align</var> at compile time, storing the result in +<var>misalign</var> if so. +</p> +</dd> +<dt>‘<samp>known_alignment (<var>value</var>)</samp>’</dt> +<dd><p>Return the minimum alignment that <var>value</var> is known to have +(in other words, the largest alignment that can be guaranteed +whatever the values of the indeterminates turn out to be). +Return 0 if <var>value</var> is known to be 0. +</p> +</dd> +<dt>‘<samp>force_align_down (<var>value</var>, <var>align</var>)</samp>’</dt> +<dd><p>Assert that <var>value</var> can be aligned down to <var>align</var> at compile +time and return the result. When using this routine, please add a +comment explaining why the assertion is known to hold. +</p> +</dd> +<dt>‘<samp>force_align_up (<var>value</var>, <var>align</var>)</samp>’</dt> +<dd><p>Likewise, but aligning up. +</p> +</dd> +<dt>‘<samp>force_align_down_and_div (<var>value</var>, <var>align</var>)</samp>’</dt> +<dd><p>Divide the result of <code>force_align_down</code> by <var>align</var>. Again, +please add a comment explaining why the assertion in <code>force_align_down</code> +is known to hold. +</p> +</dd> +<dt>‘<samp>force_align_up_and_div (<var>value</var>, <var>align</var>)</samp>’</dt> +<dd><p>Likewise for <code>force_align_up</code>. +</p> +</dd> +<dt>‘<samp>force_get_misalignment (<var>value</var>, <var>align</var>)</samp>’</dt> +<dd><p>Assert that we can calculate the misalignment of <var>value</var> with +respect to <var>align</var> at compile time and return the misalignment. +When using this function, please add a comment explaining why +the assertion is known to hold. +</p></dd> +</dl> + +<hr> +<div class="header"> +<p> +Next: <a href="Computing-bounds-on-poly_005fints.html#Computing-bounds-on-poly_005fints" accesskey="n" rel="next">Computing bounds on <code>poly_int</code>s</a>, Previous: <a href="Arithmetic-on-poly_005fints.html#Arithmetic-on-poly_005fints" accesskey="p" rel="previous">Arithmetic on <code>poly_int</code>s</a>, Up: <a href="poly_005fint.html#poly_005fint" accesskey="u" rel="up">poly_int</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> |