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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - lgdt op doesn't work in code16 block"
href="https://llvm.org/bugs/show_bug.cgi?id=31576">31576</a>
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<tr>
<th>Summary</th>
<td>lgdt op doesn't work in code16 block
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>3.9
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>LLVM assembly language parser
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>funfunctor@folklore1984.net
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=17817" name="attach_17817" title="lgdt in code16 block usage">attachment 17817</a> <a href="attachment.cgi?id=17817&action=edit" title="lgdt in code16 block usage">[details]</a></span>
lgdt in code16 block usage
Hi,
In librecore/coreboot we require the use of lgdt to get us from code16
real-mode to code32 protected-mode.
The following attached reduced test case doesn't compile with the integrated-as
of LLVM however works with binutils.
GNU as assembles it as follows:
reduced-test-case-as.o: file format elf64-x86-64
Disassembly of section .text:
0000000000000000 <gdtaddr>:
0: 00 00 add %al,(%rax)
2: 00 00 add %al,(%rax)
4: 00 00 add %al,(%rax)
6: 66 0f 01 16 data16 lgdt (%rsi)
...
$ llvm-as-3.9 --version
LLVM version 3.9.1
Kind Regards,
Edward.</pre>
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