194 lines
9.9 KiB
HTML
194 lines
9.9 KiB
HTML
<html lang="en">
|
|
<head>
|
|
<title>Sparc-Relocs - 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="Sparc_002dSyntax.html#Sparc_002dSyntax" title="Sparc-Syntax">
|
|
<link rel="prev" href="Sparc_002dConstants.html#Sparc_002dConstants" title="Sparc-Constants">
|
|
<link rel="next" href="Sparc_002dSize_002dTranslations.html#Sparc_002dSize_002dTranslations" title="Sparc-Size-Translations">
|
|
<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="Sparc-Relocs"></a>
|
|
<a name="Sparc_002dRelocs"></a>
|
|
<p>
|
|
Next: <a rel="next" accesskey="n" href="Sparc_002dSize_002dTranslations.html#Sparc_002dSize_002dTranslations">Sparc-Size-Translations</a>,
|
|
Previous: <a rel="previous" accesskey="p" href="Sparc_002dConstants.html#Sparc_002dConstants">Sparc-Constants</a>,
|
|
Up: <a rel="up" accesskey="u" href="Sparc_002dSyntax.html#Sparc_002dSyntax">Sparc-Syntax</a>
|
|
<hr>
|
|
</div>
|
|
|
|
<h5 class="subsubsection">9.44.3.4 Relocations</h5>
|
|
|
|
<p><a name="index-Sparc-relocations-2178"></a><a name="index-relocations_002c-Sparc-2179"></a>
|
|
ELF relocations are available as defined in the 32-bit and 64-bit
|
|
Sparc ELF specifications.
|
|
|
|
<p><code>R_SPARC_HI22</code> is obtained using ‘<samp><span class="samp">%hi</span></samp>’ and <code>R_SPARC_LO10</code>
|
|
is obtained using ‘<samp><span class="samp">%lo</span></samp>’. Likewise <code>R_SPARC_HIX22</code> is
|
|
obtained from ‘<samp><span class="samp">%hix</span></samp>’ and <code>R_SPARC_LOX10</code> is obtained
|
|
using ‘<samp><span class="samp">%lox</span></samp>’. For example:
|
|
|
|
<pre class="example"> sethi %hi(symbol), %g1
|
|
or %g1, %lo(symbol), %g1
|
|
|
|
sethi %hix(symbol), %g1
|
|
xor %g1, %lox(symbol), %g1
|
|
</pre>
|
|
<p>These “high” mnemonics extract bits 31:10 of their operand,
|
|
and the “low” mnemonics extract bits 9:0 of their operand.
|
|
|
|
<p>V9 code model relocations can be requested as follows:
|
|
|
|
<ul>
|
|
<li><code>R_SPARC_HH22</code> is requested using ‘<samp><span class="samp">%hh</span></samp>’. It can
|
|
also be generated using ‘<samp><span class="samp">%uhi</span></samp>’.
|
|
<li><code>R_SPARC_HM10</code> is requested using ‘<samp><span class="samp">%hm</span></samp>’. It can
|
|
also be generated using ‘<samp><span class="samp">%ulo</span></samp>’.
|
|
<li><code>R_SPARC_LM22</code> is requested using ‘<samp><span class="samp">%lm</span></samp>’.
|
|
|
|
<li><code>R_SPARC_H44</code> is requested using ‘<samp><span class="samp">%h44</span></samp>’.
|
|
<li><code>R_SPARC_M44</code> is requested using ‘<samp><span class="samp">%m44</span></samp>’.
|
|
<li><code>R_SPARC_L44</code> is requested using ‘<samp><span class="samp">%l44</span></samp>’ or ‘<samp><span class="samp">%l34</span></samp>’.
|
|
<li><code>R_SPARC_H34</code> is requested using ‘<samp><span class="samp">%h34</span></samp>’.
|
|
</ul>
|
|
|
|
<p>The ‘<samp><span class="samp">%l34</span></samp>’ generates a <code>R_SPARC_L44</code> relocation because it
|
|
calculates the necessary value, and therefore no explicit
|
|
<code>R_SPARC_L34</code> relocation needed to be created for this purpose.
|
|
|
|
<p>The ‘<samp><span class="samp">%h34</span></samp>’ and ‘<samp><span class="samp">%l34</span></samp>’ relocations are used for the abs34 code
|
|
model. Here is an example abs34 address generation sequence:
|
|
|
|
<pre class="example"> sethi %h34(symbol), %g1
|
|
sllx %g1, 2, %g1
|
|
or %g1, %l34(symbol), %g1
|
|
</pre>
|
|
<p>The PC relative relocation <code>R_SPARC_PC22</code> can be obtained by
|
|
enclosing an operand inside of ‘<samp><span class="samp">%pc22</span></samp>’. Likewise, the
|
|
<code>R_SPARC_PC10</code> relocation can be obtained using ‘<samp><span class="samp">%pc10</span></samp>’.
|
|
These are mostly used when assembling PIC code. For example, the
|
|
standard PIC sequence on Sparc to get the base of the global offset
|
|
table, PC relative, into a register, can be performed as:
|
|
|
|
<pre class="example"> sethi %pc22(_GLOBAL_OFFSET_TABLE_-4), %l7
|
|
add %l7, %pc10(_GLOBAL_OFFSET_TABLE_+4), %l7
|
|
</pre>
|
|
<p>Several relocations exist to allow the link editor to potentially
|
|
optimize GOT data references. The <code>R_SPARC_GOTDATA_OP_HIX22</code>
|
|
relocation can obtained by enclosing an operand inside of
|
|
‘<samp><span class="samp">%gdop_hix22</span></samp>’. The <code>R_SPARC_GOTDATA_OP_LOX10</code>
|
|
relocation can obtained by enclosing an operand inside of
|
|
‘<samp><span class="samp">%gdop_lox10</span></samp>’. Likewise, <code>R_SPARC_GOTDATA_OP</code> can be
|
|
obtained by enclosing an operand inside of ‘<samp><span class="samp">%gdop</span></samp>’.
|
|
For example, assuming the GOT base is in register <code>%l7</code>:
|
|
|
|
<pre class="example"> sethi %gdop_hix22(symbol), %l1
|
|
xor %l1, %gdop_lox10(symbol), %l1
|
|
ld [%l7 + %l1], %l2, %gdop(symbol)
|
|
</pre>
|
|
<p>There are many relocations that can be requested for access to
|
|
thread local storage variables. All of the Sparc TLS mnemonics
|
|
are supported:
|
|
|
|
<ul>
|
|
<li><code>R_SPARC_TLS_GD_HI22</code> is requested using ‘<samp><span class="samp">%tgd_hi22</span></samp>’.
|
|
<li><code>R_SPARC_TLS_GD_LO10</code> is requested using ‘<samp><span class="samp">%tgd_lo10</span></samp>’.
|
|
<li><code>R_SPARC_TLS_GD_ADD</code> is requested using ‘<samp><span class="samp">%tgd_add</span></samp>’.
|
|
<li><code>R_SPARC_TLS_GD_CALL</code> is requested using ‘<samp><span class="samp">%tgd_call</span></samp>’.
|
|
|
|
<li><code>R_SPARC_TLS_LDM_HI22</code> is requested using ‘<samp><span class="samp">%tldm_hi22</span></samp>’.
|
|
<li><code>R_SPARC_TLS_LDM_LO10</code> is requested using ‘<samp><span class="samp">%tldm_lo10</span></samp>’.
|
|
<li><code>R_SPARC_TLS_LDM_ADD</code> is requested using ‘<samp><span class="samp">%tldm_add</span></samp>’.
|
|
<li><code>R_SPARC_TLS_LDM_CALL</code> is requested using ‘<samp><span class="samp">%tldm_call</span></samp>’.
|
|
|
|
<li><code>R_SPARC_TLS_LDO_HIX22</code> is requested using ‘<samp><span class="samp">%tldo_hix22</span></samp>’.
|
|
<li><code>R_SPARC_TLS_LDO_LOX10</code> is requested using ‘<samp><span class="samp">%tldo_lox10</span></samp>’.
|
|
<li><code>R_SPARC_TLS_LDO_ADD</code> is requested using ‘<samp><span class="samp">%tldo_add</span></samp>’.
|
|
|
|
<li><code>R_SPARC_TLS_IE_HI22</code> is requested using ‘<samp><span class="samp">%tie_hi22</span></samp>’.
|
|
<li><code>R_SPARC_TLS_IE_LO10</code> is requested using ‘<samp><span class="samp">%tie_lo10</span></samp>’.
|
|
<li><code>R_SPARC_TLS_IE_LD</code> is requested using ‘<samp><span class="samp">%tie_ld</span></samp>’.
|
|
<li><code>R_SPARC_TLS_IE_LDX</code> is requested using ‘<samp><span class="samp">%tie_ldx</span></samp>’.
|
|
<li><code>R_SPARC_TLS_IE_ADD</code> is requested using ‘<samp><span class="samp">%tie_add</span></samp>’.
|
|
|
|
<li><code>R_SPARC_TLS_LE_HIX22</code> is requested using ‘<samp><span class="samp">%tle_hix22</span></samp>’.
|
|
<li><code>R_SPARC_TLS_LE_LOX10</code> is requested using ‘<samp><span class="samp">%tle_lox10</span></samp>’.
|
|
</ul>
|
|
|
|
<p>Here are some example TLS model sequences.
|
|
|
|
<p>First, General Dynamic:
|
|
|
|
<pre class="example"> sethi %tgd_hi22(symbol), %l1
|
|
add %l1, %tgd_lo10(symbol), %l1
|
|
add %l7, %l1, %o0, %tgd_add(symbol)
|
|
call __tls_get_addr, %tgd_call(symbol)
|
|
nop
|
|
</pre>
|
|
<p>Local Dynamic:
|
|
|
|
<pre class="example"> sethi %tldm_hi22(symbol), %l1
|
|
add %l1, %tldm_lo10(symbol), %l1
|
|
add %l7, %l1, %o0, %tldm_add(symbol)
|
|
call __tls_get_addr, %tldm_call(symbol)
|
|
nop
|
|
|
|
sethi %tldo_hix22(symbol), %l1
|
|
xor %l1, %tldo_lox10(symbol), %l1
|
|
add %o0, %l1, %l1, %tldo_add(symbol)
|
|
</pre>
|
|
<p>Initial Exec:
|
|
|
|
<pre class="example"> sethi %tie_hi22(symbol), %l1
|
|
add %l1, %tie_lo10(symbol), %l1
|
|
ld [%l7 + %l1], %o0, %tie_ld(symbol)
|
|
add %g7, %o0, %o0, %tie_add(symbol)
|
|
|
|
sethi %tie_hi22(symbol), %l1
|
|
add %l1, %tie_lo10(symbol), %l1
|
|
ldx [%l7 + %l1], %o0, %tie_ldx(symbol)
|
|
add %g7, %o0, %o0, %tie_add(symbol)
|
|
</pre>
|
|
<p>And finally, Local Exec:
|
|
|
|
<pre class="example"> sethi %tle_hix22(symbol), %l1
|
|
add %l1, %tle_lox10(symbol), %l1
|
|
add %g7, %l1, %l1
|
|
</pre>
|
|
<p>When assembling for 64-bit, and a secondary constant addend is
|
|
specified in an address expression that would normally generate
|
|
an <code>R_SPARC_LO10</code> relocation, the assembler will emit an
|
|
<code>R_SPARC_OLO10</code> instead.
|
|
|
|
</body></html>
|
|
|