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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

    }
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In the example above, the first bins construct associates bin a with the values of variable v_a between 0 and 63, and the value 65. The second bins construct creates a set of 65 bins b[127], b[128],...b[191]. Likewise, the third bins construct creates 3 bins: c[200], c[201], and c[202]. The fourth bins construct associates bin d with the values between 1000 and 1023 ($ represents the maximum value of v_a). Every value that does not match bins a, b[], c[], or d[] is added into its own distinct bin.&nbsp;</p>
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A default or default sequence bin specification cannot be explicitly ignored (see Section 20.4.4). It shall be an error for bins designated as ignore_bins to also specify a default or default sequence.&nbsp;</p>
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Generic coverage groups can be written by passing their traits as arguments to the constructor. For example: </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00874');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00874"><pre class="Element12">covergroup gc (ref int ra, int low, int high ) @(posedge clk);
    coverpoint ra // sample variable passed by reference
    {
        bins good = { [low : high] };
        bins bad[] = default;
    }
endgroup
...
int va, vb;
cg c1 = new( va, 0, 50 ); // cover variable va in the range 0 to 50
cg c2 = new( vb, 120, 600 ); // cover variable vb in the range 120 to 600</pre></div></div>
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The example above defines a coverage group, gc, in which the signal to be sampled as well as the extent of the coverage bins are specified as arguments. Later, two instances of the coverage group are created; each instance samples a different signal and covers a different range of values.</p></div>
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<a href="00856.html" target="topic">第二十章 覆盖</a></p></div>
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描述&nbsp;</div></td></tr><tr>
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<a href="00248.html" target="topic">20.4.1 Specifying bins for transitions</a>&nbsp;</div></td><td class="Element206" valign="top" width="50%">
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The syntax for specifying transition bins accepts a subset of the sequence syntax described in Section 17: &nbsp;</div></td></tr><tr>
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<a href="00249.html" target="topic">20.4.2 Automatic bin creation for coverage points</a>&nbsp;</div></td><td class="Element206" valign="top" width="50%">
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If a coverage point does not define any bins, SystemVerilog automatically creates state bins. This provides an easy-to-use mechanism for binning different values of a coverage point. Users can either let the tool automatically create state bins for coverage points or explicitly define named bins for each coverage point.<br><br>When the automatic bin creation mechanism is used, SystemVerilog creates N bins to collect the sampled values of a coverage point. The value N is determined as follows:
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<li class="Element606">For an enum coverage point, N is the cardinality of the enumeration.</li>
<li class="Element606">For any other integral coverage point, N is the minimum of... <a href="00249.html" target="topic">more</a>&nbsp;</div></td></tr><tr>
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<a href="00250.html" target="topic">20.4.3 Wildcard specification of coverage point bins</a>&nbsp;</div></td><td class="Element206" valign="top" width="50%">
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By default, a value or transition bin definition can specify 4-state values. When a bin definition includes an X or Z, it indicates that the bin count should only be incremented when the sampled value has an X or Z in the same bit positions, i.e., the comparison is done using ===. The wildcard bins definition causes all X, Z, or ? to be treated as wildcards for 0 or 1 (similar to the =?= operator). For example: &nbsp;</div></td></tr><tr>
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<a href="00251.html" target="topic">20.4.4 Excluding coverage point values or transitions</a>&nbsp;</div></td><td class="Element206" valign="top" width="50%">
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A set of values or transitions associated with a coverage-point can be explicitly excluded from coverage by specifying them as ignore_bins. For example: &nbsp;</div></td></tr><tr>
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<a href="00252.html" target="topic">20.4.5 Specifying Illegal coverage point values or transitions</a>&nbsp;</div></td><td class="Element206" valign="top" width="50%">
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A set of values or transitions associated with a coverage-point can be marked as illegal by specifying them as illegal_bins. For example: &nbsp;</div></td></tr></table></div></div>
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