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这是一本关于verilog编程语言的教程,对学习verilog语言有帮助

<div class="Element13"><div class="Element12" id="code00661"><pre class="Element12"><span style="color: #0000FF">sequence</span> s4<span style="color: #800080">;</span>
    <span style="color: #0000FF">int</span> x<span style="color: #800080">;</span>
    <span style="color: #800080">(</span>a <span style="color: #800080">##</span><span style="color: #FF0000">1</span> b<span style="color: #800080">, (</span>x <span style="color: #800080">=</span> data<span style="color: #800080">)</span> <span style="color: #800080">##</span><span style="color: #FF0000">1</span> c<span style="color: #800080">)</span> <span style="color: #0000FF">or</span> <span style="color: #800080">(</span>d <span style="color: #800080">##</span><span style="color: #FF0000">1</span><span style="color: #800080"> (</span>e<span style="color: #800080">==</span>x<span style="color: #800080">));</span> <span style="color: #008000">// 非法的</span>
<span style="color: #0000FF">endsequence</span></pre></div></div>
<p class="Element10">

<ol class="Element631">
<li value="2" class="Element601">对于<strong><span style="color: #0000FF">or</span></strong>操作的情况，当且仅当一个局部变量流出每一个操作数序列的时候，这个局部变量才流出复合序列。如果局部变量在复合序列启动之前没有被赋值并且它仅在其中的一个操作数序列被赋值，那么它不会流出复合序列。</li>
<li value="3" class="Element601">一个匹配其操作数序列的<strong><span style="color: #0000FF">or</span></strong>操作的一个操作数的每一个线程都作为一个独立的线程执行，并携带它自己的最新赋值到流出复合序列的局部变量。这些线程不必在局部变量上具有一致的计算结果。例如：</li>
</ol></p><div class="Element170">
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<div class="Element13"><div class="Element12" id="code00662"><pre class="Element12"><span style="color: #0000FF">sequence</span> s5<span style="color: #800080">;</span>
    <span style="color: #0000FF">int</span> x<span style="color: #800080">,</span>y<span style="color: #800080">;</span>
    <span style="color: #800080">((</span>a <span style="color: #800080">##</span><span style="color: #FF0000">1</span> b<span style="color: #800080">,</span> x <span style="color: #800080">=</span> data<span style="color: #800080">,</span> y <span style="color: #800080">=</span> data1 <span style="color: #800080">##</span><span style="color: #FF0000">1</span> c<span style="color: #800080">)</span>
    <span style="color: #0000FF">or</span> <span style="color: #800080">(</span>d <span style="color: #800080">##</span><span style="color: #FF0000">1</span> <span style="color: #800080">`true,</span> x <span style="color: #800080">=</span> data <span style="color: #800080">##</span><span style="color: #FF0000">0</span> <span style="color: #800080">(</span>e<span style="color: #800080">==</span>x<span style="color: #800080">)))</span> <span style="color: #800080">##</span><span style="color: #FF0000">1</span> <span style="color: #800080">(</span>y<span style="color: #800080">==</span>data2<span style="color: #800080">);</span>
    <span style="color: #008000">// 非法的，因为y没有在交集中</span>
<span style="color: #0000FF">endsequence</span>

<span style="color: #0000FF">sequence</span> s6<span style="color: #800080">;</span>
    <span style="color: #0000FF">int</span> x<span style="color: #800080">,</span>y<span style="color: #800080">;</span>
    <span style="color: #800080">((</span>a <span style="color: #800080">##</span><span style="color: #FF0000">1</span> b<span style="color: #800080">,</span> x <span style="color: #800080">=</span> data<span style="color: #800080">,</span> y <span style="color: #800080">=</span> data1 <span style="color: #800080">##</span><span style="color: #FF0000">1</span> c<span style="color: #800080">)</span>
    <span style="color: #0000FF">or</span> <span style="color: #800080">(</span>d <span style="color: #800080">##</span><span style="color: #FF0000">1</span> <span style="color: #800080">`true,</span> x <span style="color: #800080">=</span> data <span style="color: #800080">##</span><span style="color: #FF0000">0</span> <span style="color: #800080">(</span>e<span style="color: #800080">==</span>x<span style="color: #800080">)))</span> <span style="color: #800080">##</span><span style="color: #FF0000">1</span> <span style="color: #800080">(</span>x<span style="color: #800080">==</span>data2<span style="color: #800080">);</span>
    <span style="color: #008000">// 合法的，因为x位于交集中</span>
<span style="color: #0000FF">endsequence</span></pre></div></div>
<p class="Element10">

<ol class="Element631">
<li value="4" class="Element601">对于and和intersect操作的情况，从至少一个操作数流出的局部变量应该从复合序列流出，除非它被阻塞。如果下列条件中的一个条件成立，那么一个局部变量会被阻塞：
<ol class="Element632">
<li value="1" class="Element602">局部变量在复合序列的每一个操作数中或者从复合序列的每一个操作数流出时被赋值。或者，</li>
<li value="2" class="Element602">局部变量被阻塞而不能从至少一个操作数序列中流出。</li>
</ol></li>
</ol>流出复合序列的一个局部变量的值是最后所赋的值。在复合序列的计算结束的时候两个操作数的线程被合并成一个。 </p><div class="Element170">
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<div class="Element13"><div class="Element12" id="code00663"><pre class="Element12"><span style="color: #0000FF">sequence</span> s7<span style="color: #800080">;</span>
    <span style="color: #0000FF">int</span> x<span style="color: #800080">,</span>y<span style="color: #800080">;</span>
    <span style="color: #800080">((</span>a <span style="color: #800080">##</span><span style="color: #FF0000">1</span> b<span style="color: #800080">,</span> x <span style="color: #800080">=</span> data<span style="color: #800080">,</span> y <span style="color: #800080">=</span> data1 <span style="color: #800080">##</span><span style="color: #FF0000">1</span> c<span style="color: #800080">)</span>
    <span style="color: #0000FF">and</span> <span style="color: #800080">(</span>d <span style="color: #800080">##</span><span style="color: #FF0000">1</span> <span style="color: #800080">`true,</span> x <span style="color: #800080">=</span> data <span style="color: #800080">##</span><span style="color: #FF0000">0</span> <span style="color: #800080">(</span>e<span style="color: #800080">==</span>x<span style="color: #800080">)))</span> <span style="color: #800080">##</span><span style="color: #FF0000">1</span> <span style="color: #800080">(</span>x<span style="color: #800080">==</span>data2<span style="color: #800080">);</span>
    <span style="color: #008000">// 非法的，因为x对于两个线程是共用的</span>
<span style="color: #0000FF">endsequence</span>

<span style="color: #0000FF">sequence</span> s8<span style="color: #800080">;</span>
    <span style="color: #0000FF">int</span> x<span style="color: #800080">,</span>y<span style="color: #800080">;</span>
    <span style="color: #800080">((</span>a <span style="color: #800080">##</span><span style="color: #FF0000">1</span> b<span style="color: #800080">,</span> x <span style="color: #800080">=</span> data<span style="color: #800080">,</span> y <span style="color: #800080">=</span> data1 <span style="color: #800080">##</span><span style="color: #FF0000">1</span> c<span style="color: #800080">)</span>
    <span style="color: #0000FF">or</span> <span style="color: #800080">(</span>d <span style="color: #800080">##</span><span style="color: #FF0000">1</span> <span style="color: #800080">`true,</span> x <span style="color: #800080">=</span> data <span style="color: #800080">##</span><span style="color: #FF0000">0</span> <span style="color: #800080">(</span>e<span style="color: #800080">==</span>x<span style="color: #800080">)))</span> <span style="color: #800080">##</span><span style="color: #FF0000">1</span> <span style="color: #800080">(</span>y<span style="color: #800080">==</span>data2<span style="color: #800080">);</span>
    <span style="color: #008000">// legal since y is in the difference</span>
<span style="color: #0000FF">endsequence</span></pre></div></div>
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