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    <head>
      <base href="http://llvm.org/bugs/" />
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - MMX registers have incorrect values"
   href="http://llvm.org/bugs/show_bug.cgi?id=18594">18594</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>MMX registers have incorrect values
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>lldb
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>3.2
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>All
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>All Bugs
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>lldb-dev@cs.uiuc.edu
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>richard@codersnotes.com
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=11926" name="attach_11926" title="Program to demonstrate the bug">attachment 11926</a> <a href="attachment.cgi?id=11926&action=edit" title="Program to demonstrate the bug">[details]</a></span>
Program to demonstrate the bug

MMX registers are not aliased correctly with the floating point registers.

To reproduce, compile and run the attached program until it hits the int3
breakpoint.

The program first prints the correct value of MM7 to stdout for reference. It
then performs the same test again except this time drops you at a breakpoint.

Type "register read mm7" into lldb. Compare against the value printed by the
test program. Notice they do not match.

Example:

$ clang fpbug.c -g -o fpbug
$ lldb fpbug
Current executable set to 'fpbug' (x86_64).
(lldb) run
Process 4301 launched: '/home/kayamon/fpbug' (x86_64)
MM7 should contain: c0e4000000000000
Process 4301 stopped
(lldb) register read mm7
     mm7 = 0x0000000000000000</pre>
        </div>
      </p>
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