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<a href="../../da/d21/memcmp_8S.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span> /*-</div>
<div class="line"><a name="l00002"></a><span class="lineno"> 2</span>  * Copyright (c) 2002-2018 The UbixOS Project.</div>
<div class="line"><a name="l00003"></a><span class="lineno"> 3</span>  * All rights reserved.</div>
<div class="line"><a name="l00004"></a><span class="lineno"> 4</span>  *</div>
<div class="line"><a name="l00005"></a><span class="lineno"> 5</span>  * This was developed by Christopher W. Olsen for the UbixOS Project.</div>
<div class="line"><a name="l00006"></a><span class="lineno"> 6</span>  *</div>
<div class="line"><a name="l00007"></a><span class="lineno"> 7</span>  * Redistribution and use in source and binary forms, with or without modification, are permitted</div>
<div class="line"><a name="l00008"></a><span class="lineno"> 8</span>  * provided that the following conditions are met:</div>
<div class="line"><a name="l00009"></a><span class="lineno"> 9</span>  *</div>
<div class="line"><a name="l00010"></a><span class="lineno"> 10</span>  * 1) Redistributions of source code must retain the above copyright notice, this list of</div>
<div class="line"><a name="l00011"></a><span class="lineno"> 11</span>  * conditions, the following disclaimer and the list of authors.</div>
<div class="line"><a name="l00012"></a><span class="lineno"> 12</span>  * 2) Redistributions in binary form must reproduce the above copyright notice, this list of</div>
<div class="line"><a name="l00013"></a><span class="lineno"> 13</span>  * conditions, the following disclaimer and the list of authors in the documentation and/or</div>
<div class="line"><a name="l00014"></a><span class="lineno"> 14</span>  * other materials provided with the distribution.</div>
<div class="line"><a name="l00015"></a><span class="lineno"> 15</span>  * 3) Neither the name of the UbixOS Project nor the names of its contributors may be used to</div>
<div class="line"><a name="l00016"></a><span class="lineno"> 16</span>  * endorse or promote products derived from this software without specific prior written</div>
<div class="line"><a name="l00017"></a><span class="lineno"> 17</span>  * permission.</div>
<div class="line"><a name="l00018"></a><span class="lineno"> 18</span>  *</div>
<div class="line"><a name="l00019"></a><span class="lineno"> 19</span>  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED</div>
<div class="line"><a name="l00020"></a><span class="lineno"> 20</span>  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS</div>
<div class="line"><a name="l00021"></a><span class="lineno"> 21</span>  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS</div>
<div class="line"><a name="l00022"></a><span class="lineno"> 22</span>  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES</div>
<div class="line"><a name="l00023"></a><span class="lineno"> 23</span>  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,</div>
<div class="line"><a name="l00024"></a><span class="lineno"> 24</span>  * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN</div>
<div class="line"><a name="l00025"></a><span class="lineno"> 25</span>  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT</div>
<div class="line"><a name="l00026"></a><span class="lineno"> 26</span>  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.</div>
<div class="line"><a name="l00027"></a><span class="lineno"> 27</span>  */</div>
<div class="line"><a name="l00028"></a><span class="lineno"> 28</span> </div>
<div class="line"><a name="l00029"></a><span class="lineno"> 29</span>  #include <i386/asmacros.h></div>
<div class="line"><a name="l00030"></a><span class="lineno"> 30</span> </div>
<div class="line"><a name="l00031"></a><span class="lineno"> 31</span> ENTRY(memcmp)</div>
<div class="line"><a name="l00032"></a><span class="lineno"> 32</span>  pushl %edi</div>
<div class="line"><a name="l00033"></a><span class="lineno"> 33</span>  pushl %esi</div>
<div class="line"><a name="l00034"></a><span class="lineno"> 34</span>  movl 12(%esp),%edi</div>
<div class="line"><a name="l00035"></a><span class="lineno"> 35</span>  movl 16(%esp),%esi</div>
<div class="line"><a name="l00036"></a><span class="lineno"> 36</span>  cld /* set compare direction forward */</div>
<div class="line"><a name="l00037"></a><span class="lineno"> 37</span> </div>
<div class="line"><a name="l00038"></a><span class="lineno"> 38</span>  movl 20(%esp),%ecx /* compare by words */</div>
<div class="line"><a name="l00039"></a><span class="lineno"> 39</span>  shrl $2,%ecx</div>
<div class="line"><a name="l00040"></a><span class="lineno"> 40</span>  repe</div>
<div class="line"><a name="l00041"></a><span class="lineno"> 41</span>  cmpsl</div>
<div class="line"><a name="l00042"></a><span class="lineno"> 42</span>  jne L5 /* do we match so far? */</div>
<div class="line"><a name="l00043"></a><span class="lineno"> 43</span> </div>
<div class="line"><a name="l00044"></a><span class="lineno"> 44</span>  movl 20(%esp),%ecx /* compare remainder by bytes */</div>
<div class="line"><a name="l00045"></a><span class="lineno"> 45</span>  andl $3,%ecx</div>
<div class="line"><a name="l00046"></a><span class="lineno"> 46</span>  repe</div>
<div class="line"><a name="l00047"></a><span class="lineno"> 47</span>  cmpsb</div>
<div class="line"><a name="l00048"></a><span class="lineno"> 48</span>  jne L6 /* do we match? */</div>
<div class="line"><a name="l00049"></a><span class="lineno"> 49</span> </div>
<div class="line"><a name="l00050"></a><span class="lineno"> 50</span>  xorl %eax,%eax /* we match, return zero */</div>
<div class="line"><a name="l00051"></a><span class="lineno"> 51</span>  popl %esi</div>
<div class="line"><a name="l00052"></a><span class="lineno"> 52</span>  popl %edi</div>
<div class="line"><a name="l00053"></a><span class="lineno"> 53</span>  ret</div>
<div class="line"><a name="l00054"></a><span class="lineno"> 54</span> </div>
<div class="line"><a name="l00055"></a><span class="lineno"> 55</span> L5: movl $4,%ecx /* We know that one of the next */</div>
<div class="line"><a name="l00056"></a><span class="lineno"> 56</span>  subl %ecx,%edi /* four pairs of bytes do not */</div>
<div class="line"><a name="l00057"></a><span class="lineno"> 57</span>  subl %ecx,%esi /* match. */</div>
<div class="line"><a name="l00058"></a><span class="lineno"> 58</span>  repe</div>
<div class="line"><a name="l00059"></a><span class="lineno"> 59</span>  cmpsb</div>
<div class="line"><a name="l00060"></a><span class="lineno"> 60</span> L6: movzbl -1(%edi),%eax /* Perform unsigned comparison */</div>
<div class="line"><a name="l00061"></a><span class="lineno"> 61</span>  movzbl -1(%esi),%edx</div>
<div class="line"><a name="l00062"></a><span class="lineno"> 62</span>  subl %edx,%eax</div>
<div class="line"><a name="l00063"></a><span class="lineno"> 63</span>  popl %esi</div>
<div class="line"><a name="l00064"></a><span class="lineno"> 64</span>  popl %edi</div>
<div class="line"><a name="l00065"></a><span class="lineno"> 65</span>  ret</div>
<div class="line"><a name="l00066"></a><span class="lineno"> 66</span> END(memcmp)</div>
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