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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - data32 prefix in .code16 block is not respected"
href="https://bugs.llvm.org/show_bug.cgi?id=46942">46942</a>
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<th>Summary</th>
<td>data32 prefix in .code16 block is not respected
</td>
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<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Backend: X86
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>i@maskray.me
</td>
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<th>CC</th>
<td>craig.topper@gmail.com, llvm-bugs@lists.llvm.org, llvm-dev@redking.me.uk, spatel+llvm@rotateright.com
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<pre># clang newer than 2020-07-30 is needed, otherwise there are other issues:
`unrecognized driver option -e`, `unrecognized infix operator !`, and a '*'
parser issue fixed by <a href="https://reviews.llvm.org/D84895">https://reviews.llvm.org/D84895</a>
git clone git://git.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git
cd kexec-tools
./bootstrap
./configure CC=clang
make -j10
This failed with a linker error, which is a red herring.
# ld: error: kexec_test/kexec_test.o:(.text+0x104): relocation R_386_16 out of
range: 68320 is not in [-32768, 65535]
One issue I have noticed:
% cat a.s
.code16
callw test16
data32 call real_to_prot ## the operand is 32-bit in GNU as but 16-bit in
MC
real_to_prot:
ret
% as --32 a.s -o a.o
% llvm-mc -filetype=obj -triple=i386 a.s -o b.o
% diff -u =(objdump -drz a.o) =(objdump -drz b.o)
...
-00000000 <real_to_prot-0x9>:
- 0: e8 fe ff 66 e8 call e8670003 <real_to_prot+0xe866fffa>
+00000000 <real_to_prot-0x7>:
+ 0: e8 fe ff 66 e8 call e8670003 <real_to_prot+0xe866fffc>
1: R_386_PC16 test16
5: 00 00 add %al,(%eax)
- 7: 00 00 add %al,(%eax)
-00000009 <real_to_prot>:
- 9: c3 ret
+00000007 <real_to_prot>:
+ 7: c3 ret</pre>
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