toolchain/share/doc/as.html/GNU-Object-Attributes.html

130 lines
5.6 KiB
HTML
Raw Permalink Normal View History

2024-01-10 05:24:32 +00:00
<html lang="en">
<head>
<title>GNU Object Attributes - Using as</title>
<meta http-equiv="Content-Type" content="text/html">
<meta name="description" content="Using as">
<meta name="generator" content="makeinfo 4.13">
<link title="Top" rel="start" href="index.html#Top">
<link rel="up" href="Object-Attributes.html#Object-Attributes" title="Object Attributes">
<link rel="next" href="Defining-New-Object-Attributes.html#Defining-New-Object-Attributes" title="Defining New Object Attributes">
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
<!--
This file documents the GNU Assembler "as".
Copyright (C) 1991-2019 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 no Invariant Sections, with no Front-Cover Texts, and with no
Back-Cover Texts. A copy of the license is included in the
section entitled ``GNU Free Documentation License''.
-->
<meta http-equiv="Content-Style-Type" content="text/css">
<style type="text/css"><!--
pre.display { font-family:inherit }
pre.format { font-family:inherit }
pre.smalldisplay { font-family:inherit; font-size:smaller }
pre.smallformat { font-family:inherit; font-size:smaller }
pre.smallexample { font-size:smaller }
pre.smalllisp { font-size:smaller }
span.sc { font-variant:small-caps }
span.roman { font-family:serif; font-weight:normal; }
span.sansserif { font-family:sans-serif; font-weight:normal; }
--></style>
</head>
<body>
<div class="node">
<a name="GNU-Object-Attributes"></a>
<p>
Next:&nbsp;<a rel="next" accesskey="n" href="Defining-New-Object-Attributes.html#Defining-New-Object-Attributes">Defining New Object Attributes</a>,
Up:&nbsp;<a rel="up" accesskey="u" href="Object-Attributes.html#Object-Attributes">Object Attributes</a>
<hr>
</div>
<h3 class="section">8.1 <span class="sc">gnu</span> Object Attributes</h3>
<p>The <code>.gnu_attribute</code> directive records an object attribute
with vendor &lsquo;<samp><span class="samp">gnu</span></samp>&rsquo;.
<p>Except for &lsquo;<samp><span class="samp">Tag_compatibility</span></samp>&rsquo;, which has both an integer and a string for
its value, <span class="sc">gnu</span> attributes have a string value if the tag number is odd and
an integer value if the tag number is even. The second bit (<var>tag</var><code> &amp;
2</code> is set for architecture-independent attributes and clear for
architecture-dependent ones.
<h4 class="subsection">8.1.1 Common <span class="sc">gnu</span> attributes</h4>
<p>These attributes are valid on all architectures.
<dl>
<dt><span class="roman">Tag_compatibility (32)</span><dd>The compatibility attribute takes an integer flag value and a vendor name. If
the flag value is 0, the file is compatible with other toolchains. If it is 1,
then the file is only compatible with the named toolchain. If it is greater
than 1, the file can only be processed by other toolchains under some private
arrangement indicated by the flag value and the vendor name.
</dl>
<h4 class="subsection">8.1.2 MIPS Attributes</h4>
<dl>
<dt><span class="roman">Tag_GNU_MIPS_ABI_FP (4)</span><dd>The floating-point ABI used by this object file. The value will be:
<ul>
<li>0 for files not affected by the floating-point ABI.
<li>1 for files using the hardware floating-point ABI with a standard
double-precision FPU.
<li>2 for files using the hardware floating-point ABI with a single-precision FPU.
<li>3 for files using the software floating-point ABI.
<li>4 for files using the deprecated hardware floating-point ABI which used 64-bit
floating-point registers, 32-bit general-purpose registers and increased the
number of callee-saved floating-point registers.
<li>5 for files using the hardware floating-point ABI with a double-precision FPU
with either 32-bit or 64-bit floating-point registers and 32-bit
general-purpose registers.
<li>6 for files using the hardware floating-point ABI with 64-bit floating-point
registers and 32-bit general-purpose registers.
<li>7 for files using the hardware floating-point ABI with 64-bit floating-point
registers, 32-bit general-purpose registers and a rule that forbids the
direct use of odd-numbered single-precision floating-point registers.
</ul>
</dl>
<h4 class="subsection">8.1.3 PowerPC Attributes</h4>
<dl>
<dt><span class="roman">Tag_GNU_Power_ABI_FP (4)</span><dd>The floating-point ABI used by this object file. The value will be:
<ul>
<li>0 for files not affected by the floating-point ABI.
<li>1 for files using double-precision hardware floating-point ABI.
<li>2 for files using the software floating-point ABI.
<li>3 for files using single-precision hardware floating-point ABI.
</ul>
<br><dt><span class="roman">Tag_GNU_Power_ABI_Vector (8)</span><dd>The vector ABI used by this object file. The value will be:
<ul>
<li>0 for files not affected by the vector ABI.
<li>1 for files using general purpose registers to pass vectors.
<li>2 for files using AltiVec registers to pass vectors.
<li>3 for files using SPE registers to pass vectors.
</ul>
</dl>
<h4 class="subsection">8.1.4 IBM z Systems Attributes</h4>
<dl>
<dt><span class="roman">Tag_GNU_S390_ABI_Vector (8)</span><dd>The vector ABI used by this object file. The value will be:
<ul>
<li>0 for files not affected by the vector ABI.
<li>1 for files using software vector ABI.
<li>2 for files using hardware vector ABI.
</ul>
</dl>
</body></html>