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180 lines
8.9 KiB
HTML
180 lines
8.9 KiB
HTML
4 years ago
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<!-- This file documents the GNU Assembler "as".
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Copyright (C) 1991-2019 Free Software Foundation, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3
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or any later version published by the Free Software Foundation;
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with no Invariant Sections, with no Front-Cover Texts, and with no
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Back-Cover Texts. A copy of the license is included in the
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section entitled "GNU Free Documentation License".
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-->
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<!-- Created by GNU Texinfo 6.4, http://www.gnu.org/software/texinfo/ -->
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<head>
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<title>Xtensa Options (Using as)</title>
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<meta name="description" content="Xtensa Options (Using as)">
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<meta name="keywords" content="Xtensa Options (Using as)">
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<meta name="resource-type" content="document">
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<meta name="distribution" content="global">
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<meta name="Generator" content="makeinfo">
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<link href="index.html#Top" rel="start" title="Top">
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<link href="AS-Index.html#AS-Index" rel="index" title="AS Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="Xtensa_002dDependent.html#Xtensa_002dDependent" rel="up" title="Xtensa-Dependent">
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<link href="Xtensa-Syntax.html#Xtensa-Syntax" rel="next" title="Xtensa Syntax">
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<link href="Xtensa_002dDependent.html#Xtensa_002dDependent" rel="prev" title="Xtensa-Dependent">
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<style type="text/css">
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</style>
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</head>
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<body lang="en">
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<a name="Xtensa-Options"></a>
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<div class="header">
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<p>
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Next: <a href="Xtensa-Syntax.html#Xtensa-Syntax" accesskey="n" rel="next">Xtensa Syntax</a>, Up: <a href="Xtensa_002dDependent.html#Xtensa_002dDependent" accesskey="u" rel="up">Xtensa-Dependent</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="AS-Index.html#AS-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<a name="Command_002dline-Options-2"></a>
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<h4 class="subsection">9.54.1 Command-line Options</h4>
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<dl compact="compact">
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<dt><code>--text-section-literals | --no-text-section-literals</code></dt>
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<dd><a name="index-_002d_002dtext_002dsection_002dliterals"></a>
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<a name="index-_002d_002dno_002dtext_002dsection_002dliterals"></a>
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<p>Control the treatment of literal pools. The default is
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‘<samp>--no-text-section-literals</samp>’, which places literals in
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separate sections in the output file. This allows the literal pool to be
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placed in a data RAM/ROM. With ‘<samp>--text-section-literals</samp>’, the
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literals are interspersed in the text section in order to keep them as
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close as possible to their references. This may be necessary for large
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assembly files, where the literals would otherwise be out of range of the
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<code>L32R</code> instructions in the text section. Literals are grouped into
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pools following <code>.literal_position</code> directives or preceding
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<code>ENTRY</code> instructions. These options only affect literals referenced
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via PC-relative <code>L32R</code> instructions; literals for absolute mode
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<code>L32R</code> instructions are handled separately.
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See <a href="Literal-Directive.html#Literal-Directive">literal</a>.
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</p>
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</dd>
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<dt><code>--auto-litpools | --no-auto-litpools</code></dt>
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<dd><a name="index-_002d_002dauto_002dlitpools"></a>
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<a name="index-_002d_002dno_002dauto_002dlitpools"></a>
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<p>Control the treatment of literal pools. The default is
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‘<samp>--no-auto-litpools</samp>’, which in the absence of
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‘<samp>--text-section-literals</samp>’ places literals in separate sections
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in the output file. This allows the literal pool to be placed in a data
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RAM/ROM. With ‘<samp>--auto-litpools</samp>’, the literals are interspersed
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in the text section in order to keep them as close as possible to their
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references, explicit <code>.literal_position</code> directives are not
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required. This may be necessary for very large functions, where single
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literal pool at the beginning of the function may not be reachable by
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<code>L32R</code> instructions at the end. These options only affect
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literals referenced via PC-relative <code>L32R</code> instructions; literals
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for absolute mode <code>L32R</code> instructions are handled separately.
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When used together with ‘<samp>--text-section-literals</samp>’,
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‘<samp>--auto-litpools</samp>’ takes precedence.
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See <a href="Literal-Directive.html#Literal-Directive">literal</a>.
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</p>
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</dd>
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<dt><code>--absolute-literals | --no-absolute-literals</code></dt>
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<dd><a name="index-_002d_002dabsolute_002dliterals"></a>
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<a name="index-_002d_002dno_002dabsolute_002dliterals"></a>
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<p>Indicate to the assembler whether <code>L32R</code> instructions use absolute
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or PC-relative addressing. If the processor includes the absolute
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addressing option, the default is to use absolute <code>L32R</code>
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relocations. Otherwise, only the PC-relative <code>L32R</code> relocations
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can be used.
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</p>
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</dd>
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<dt><code>--target-align | --no-target-align</code></dt>
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<dd><a name="index-_002d_002dtarget_002dalign"></a>
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<a name="index-_002d_002dno_002dtarget_002dalign"></a>
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<p>Enable or disable automatic alignment to reduce branch penalties at some
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expense in code size. See <a href="Xtensa-Automatic-Alignment.html#Xtensa-Automatic-Alignment">Automatic
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Instruction Alignment</a>. This optimization is enabled by default. Note
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that the assembler will always align instructions like <code>LOOP</code> that
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have fixed alignment requirements.
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</p>
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</dd>
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<dt><code>--longcalls | --no-longcalls</code></dt>
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<dd><a name="index-_002d_002dlongcalls"></a>
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<a name="index-_002d_002dno_002dlongcalls"></a>
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<p>Enable or disable transformation of call instructions to allow calls
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across a greater range of addresses. See <a href="Xtensa-Call-Relaxation.html#Xtensa-Call-Relaxation">Function Call Relaxation</a>. This option should be used when call
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targets can potentially be out of range. It may degrade both code size
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and performance, but the linker can generally optimize away the
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unnecessary overhead when a call ends up within range. The default is
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‘<samp>--no-longcalls</samp>’.
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</p>
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</dd>
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<dt><code>--transform | --no-transform</code></dt>
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<dd><a name="index-_002d_002dtransform"></a>
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<a name="index-_002d_002dno_002dtransform"></a>
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<p>Enable or disable all assembler transformations of Xtensa instructions,
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including both relaxation and optimization. The default is
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‘<samp>--transform</samp>’; ‘<samp>--no-transform</samp>’ should only be used in the
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rare cases when the instructions must be exactly as specified in the
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assembly source. Using ‘<samp>--no-transform</samp>’ causes out of range
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instruction operands to be errors.
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</p>
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</dd>
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<dt><code>--rename-section <var>oldname</var>=<var>newname</var></code></dt>
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<dd><a name="index-_002d_002drename_002dsection"></a>
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<p>Rename the <var>oldname</var> section to <var>newname</var>. This option can be used
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multiple times to rename multiple sections.
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</p>
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</dd>
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<dt><code>--trampolines | --no-trampolines</code></dt>
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<dd><a name="index-_002d_002dtrampolines"></a>
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<a name="index-_002d_002dno_002dtrampolines"></a>
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<p>Enable or disable transformation of jump instructions to allow jumps
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across a greater range of addresses. See <a href="Xtensa-Jump-Relaxation.html#Xtensa-Jump-Relaxation">Jump Trampolines</a>. This option should be used when jump targets can
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potentially be out of range. In the absence of such jumps this option
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does not affect code size or performance. The default is
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‘<samp>--trampolines</samp>’.
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</p></dd>
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</dl>
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<hr>
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<div class="header">
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<p>
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Next: <a href="Xtensa-Syntax.html#Xtensa-Syntax" accesskey="n" rel="next">Xtensa Syntax</a>, Up: <a href="Xtensa_002dDependent.html#Xtensa_002dDependent" accesskey="u" rel="up">Xtensa-Dependent</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="AS-Index.html#AS-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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</body>
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</html>
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