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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - mips disassembly does not sign-extend immediate operand (daddiu, others?)"
href="http://llvm.org/bugs/show_bug.cgi?id=17539">17539</a>
</td>
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<th>Summary</th>
<td>mips disassembly does not sign-extend immediate operand (daddiu, others?)
</td>
</tr>
<tr>
<th>Product</th>
<td>new-bugs
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>FreeBSD
</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>new bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>emaste@freebsd.org
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>I'm adding MIPS support to LLDB and see that daddiu's 16-bit immediate operand
is not interpreted properly:
(lldb) disass
libc.so.7`__raise:
0x16019e8e0: daddiu $sp, $sp, 65504
0x16019e8e4: sd $ra, 16($sp)
...
it is a 16-bit signed value; 65504 should be -32
Mips64InstrInfo.td
def DADDiu : ArithLogicI<"daddiu", simm16_64, GPR64Opnd, IIArith,
immSExt16, add>,
ADDI_FM<0x19>, IsAsCheapAsAMove;
MipsGenDisassemblerTables.inc
case 159:
tmp = fieldFromInstruction(insn, 16, 5);
if (DecodeGPR64RegisterClass(MI, tmp, Address, Decoder) ==
MCDisassembler::Fail) return MCDisassembler::Fail;
tmp = fieldFromInstruction(insn, 21, 5);
if (DecodeGPR64RegisterClass(MI, tmp, Address, Decoder) ==
MCDisassembler::Fail) return MCDisassembler::Fail;
tmp = fieldFromInstruction(insn, 0, 16);
MI.addOperand(MCOperand::CreateImm(tmp));
return S;</pre>
</div>
</p>
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