ceph/src/boost/libs/context/doc/html/context/econtext/rationale/x86_and_floating_point_env.html

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  26 <div class="titlepage"><div><div><h4 class="title">
  27 <a name="context.econtext.rationale.x86_and_floating_point_env"></a><a class="link" href="x86_and_floating_point_env.html" title="x86 and floating-point env">x86
  28         and floating-point env</a>
  29 </h4></div></div></div>
  30 <h6>
  31 <a name="context.econtext.rationale.x86_and_floating_point_env.h0"></a>
  32           <span><a name="context.econtext.rationale.x86_and_floating_point_env.i386"></a></span><a class="link" href="x86_and_floating_point_env.html#context.econtext.rationale.x86_and_floating_point_env.i386">i386</a>
  33         </h6>
  34 <p>
  35           "The FpCsr and the MxCsr register must be saved and restored before
  36           any call or return by any procedure that needs to modify them ..."
  37           <sup>[<a name="context.econtext.rationale.x86_and_floating_point_env.f0" href="#ftn.context.econtext.rationale.x86_and_floating_point_env.f0" class="footnote">4</a>]</sup>.
  38         </p>
  39 <h6>
  40 <a name="context.econtext.rationale.x86_and_floating_point_env.h1"></a>
  41           <span><a name="context.econtext.rationale.x86_and_floating_point_env.x86_64"></a></span><a class="link" href="x86_and_floating_point_env.html#context.econtext.rationale.x86_and_floating_point_env.x86_64">x86_64</a>
  42         </h6>
  43 <h6>
  44 <a name="context.econtext.rationale.x86_and_floating_point_env.h2"></a>
  45           <span><a name="context.econtext.rationale.x86_and_floating_point_env.windows"></a></span><a class="link" href="x86_and_floating_point_env.html#context.econtext.rationale.x86_and_floating_point_env.windows">Windows</a>
  46         </h6>
  47 <p>
  48           MxCsr - "A callee that modifies any of the non-volatile fields within
  49           MxCsr must restore them before returning to its caller. Furthermore, a
  50           caller that has modified any of these fields must restore them to their
  51           standard values before invoking a callee ..." <sup>[<a name="context.econtext.rationale.x86_and_floating_point_env.f1" href="#ftn.context.econtext.rationale.x86_and_floating_point_env.f1" class="footnote">5</a>]</sup>.
  52         </p>
  53 <p>
  54           FpCsr - "A callee that modifies any of the fields within FpCsr must
  55           restore them before returning to its caller. Furthermore, a caller that
  56           has modified any of these fields must restore them to their standard values
  57           before invoking a callee ..." <sup>[<a name="context.econtext.rationale.x86_and_floating_point_env.f2" href="#ftn.context.econtext.rationale.x86_and_floating_point_env.f2" class="footnote">6</a>]</sup>.
  58         </p>
  59 <p>
  60           "The MMX and floating-point stack registers (MM0-MM7/ST0-ST7) are
  61           preserved across context switches. There is no explicit calling convention
  62           for these registers." <sup>[<a name="context.econtext.rationale.x86_and_floating_point_env.f3" href="#ftn.context.econtext.rationale.x86_and_floating_point_env.f3" class="footnote">7</a>]</sup>.
  63         </p>
  64 <p>
  65           "The 64-bit Microsoft compiler does not use ST(0)-ST(7)/MM0-MM7".
  66           <sup>[<a name="context.econtext.rationale.x86_and_floating_point_env.f4" href="#ftn.context.econtext.rationale.x86_and_floating_point_env.f4" class="footnote">8</a>]</sup>.
  67         </p>
  68 <p>
  69           "XMM6-XMM15 must be preserved" <sup>[<a name="context.econtext.rationale.x86_and_floating_point_env.f5" href="#ftn.context.econtext.rationale.x86_and_floating_point_env.f5" class="footnote">9</a>]</sup>
  70         </p>
  71 <h6>
  72 <a name="context.econtext.rationale.x86_and_floating_point_env.h3"></a>
  73           <span><a name="context.econtext.rationale.x86_and_floating_point_env.sysv"></a></span><a class="link" href="x86_and_floating_point_env.html#context.econtext.rationale.x86_and_floating_point_env.sysv">SysV</a>
  74         </h6>
  75 <p>
  76           "The control bits of the MxCsr register are callee-saved (preserved
  77           across calls), while the status bits are caller-saved (not preserved).
  78           The x87 status word register is caller-saved, whereas the x87 control word
  79           (FpCsr) is callee-saved." <sup>[<a name="context.econtext.rationale.x86_and_floating_point_env.f6" href="#ftn.context.econtext.rationale.x86_and_floating_point_env.f6" class="footnote">10</a>]</sup>.
  80         </p>
  81 <div class="footnotes">
  82 <br><hr width="100" align="left">
  83 <div class="footnote"><p><sup>[<a name="ftn.context.econtext.rationale.x86_and_floating_point_env.f0" href="#context.econtext.rationale.x86_and_floating_point_env.f0" class="para">4</a>] </sup>
  84             'Calling Conventions', Agner Fog
  85           </p></div>
  86 <div class="footnote"><p><sup>[<a name="ftn.context.econtext.rationale.x86_and_floating_point_env.f1" href="#context.econtext.rationale.x86_and_floating_point_env.f1" class="para">5</a>] </sup>
  87             <a href="http://http://msdn.microsoft.com/en-us/library/yxty7t75.aspx" target="_top">MSDN
  88             article 'MxCsr'</a>
  89           </p></div>
  90 <div class="footnote"><p><sup>[<a name="ftn.context.econtext.rationale.x86_and_floating_point_env.f2" href="#context.econtext.rationale.x86_and_floating_point_env.f2" class="para">6</a>] </sup>
  91             <a href="http://http://msdn.microsoft.com/en-us/library/ms235300.aspx" target="_top">MSDN
  92             article 'FpCsr'</a>
  93           </p></div>
  94 <div class="footnote"><p><sup>[<a name="ftn.context.econtext.rationale.x86_and_floating_point_env.f3" href="#context.econtext.rationale.x86_and_floating_point_env.f3" class="para">7</a>] </sup>
  95             <a href="http://msdn.microsoft.com/en-us/library/a32tsf7t%28VS.80%29.aspx" target="_top">MSDN
  96             article 'Legacy Floating-Point Support'</a>
  97           </p></div>
  98 <div class="footnote"><p><sup>[<a name="ftn.context.econtext.rationale.x86_and_floating_point_env.f4" href="#context.econtext.rationale.x86_and_floating_point_env.f4" class="para">8</a>] </sup>
  99             'Calling Conventions', Agner Fog
 100           </p></div>
 101 <div class="footnote"><p><sup>[<a name="ftn.context.econtext.rationale.x86_and_floating_point_env.f5" href="#context.econtext.rationale.x86_and_floating_point_env.f5" class="para">9</a>] </sup>
 102             <a href="http://msdn.microsoft.com/en-us/library/9z1stfyw%28v=vs.100%29.aspx" target="_top">MSDN
 103             article 'Register Usage'</a>
 104           </p></div>
 105 <div class="footnote"><p><sup>[<a name="ftn.context.econtext.rationale.x86_and_floating_point_env.f6" href="#context.econtext.rationale.x86_and_floating_point_env.f6" class="para">10</a>] </sup>
 106             SysV ABI AMD64 Architecture Processor Supplement Draft Version 0.99.4,
 107             3.2.1
 108           </p></div>
 109 </div>
 110 </div>
 111 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 112 <td align="left"></td>
 113 <td align="right"><div class="copyright-footer">Copyright &#169; 2014 Oliver Kowalke<p>
 114         Distributed under the Boost Software License, Version 1.0. (See accompanying
 115         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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