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72 lines
3.0 KiB
HTML
72 lines
3.0 KiB
HTML
4 years ago
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<html lang="en">
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<head>
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<title>ARM Mapping Symbols - Using as</title>
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<meta http-equiv="Content-Type" content="text/html">
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<meta name="description" content="Using as">
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<meta name="generator" content="makeinfo 4.13">
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<link title="Top" rel="start" href="index.html#Top">
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<link rel="up" href="ARM_002dDependent.html#ARM_002dDependent" title="ARM-Dependent">
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<link rel="prev" href="ARM-Opcodes.html#ARM-Opcodes" title="ARM Opcodes">
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<link rel="next" href="ARM-Unwinding-Tutorial.html#ARM-Unwinding-Tutorial" title="ARM Unwinding Tutorial">
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<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
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<!--
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This file documents the GNU Assembler "as".
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Copyright (C) 1991-2015 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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<style type="text/css"><!--
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span.roman { font-family:serif; font-weight:normal; }
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span.sansserif { font-family:sans-serif; font-weight:normal; }
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--></style>
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</head>
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<body>
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<div class="node">
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<a name="ARM-Mapping-Symbols"></a>
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<p>
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Next: <a rel="next" accesskey="n" href="ARM-Unwinding-Tutorial.html#ARM-Unwinding-Tutorial">ARM Unwinding Tutorial</a>,
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Previous: <a rel="previous" accesskey="p" href="ARM-Opcodes.html#ARM-Opcodes">ARM Opcodes</a>,
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Up: <a rel="up" accesskey="u" href="ARM_002dDependent.html#ARM_002dDependent">ARM-Dependent</a>
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<hr>
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</div>
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<h4 class="subsection">9.4.6 Mapping Symbols</h4>
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<p>The ARM ELF specification requires that special symbols be inserted
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into object files to mark certain features:
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<a name="index-g_t_0040code_007b_0024a_007d-779"></a>
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<dl><dt><code>$a</code><dd>At the start of a region of code containing ARM instructions.
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<p><a name="index-g_t_0040code_007b_0024t_007d-780"></a><br><dt><code>$t</code><dd>At the start of a region of code containing THUMB instructions.
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<p><a name="index-g_t_0040code_007b_0024d_007d-781"></a><br><dt><code>$d</code><dd>At the start of a region of data.
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</dl>
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<p>The assembler will automatically insert these symbols for you - there
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is no need to code them yourself. Support for tagging symbols ($b,
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$f, $p and $m) which is also mentioned in the current ARM ELF
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specification is not implemented. This is because they have been
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dropped from the new EABI and so tools cannot rely upon their
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presence.
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</body></html>
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