⭐ 欢迎来到虫虫下载站！ | 📦 资源下载 📁 资源专辑 ℹ️ 关于我们
⭐ 虫虫下载站
📤 上传资源

📄 00530.html

📁 这是一本关于verilog编程语言的教程,对学习verilog语言有帮助
💻 HTML
字号:
🔍 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN">
<html>
<head>
<title>4.7 数组赋值</title>
    <meta http-equiv="Content-Type" content="text/html; charset=GB2312" />
    <meta name="generator" content="Doc-O-Matic" />
    <meta http-equiv="Content-Style-Type" content="text/css" />
    <link rel="STYLESHEET" href="default.css" type="text/css" />

<script type="text/javascript" src="scripts.js"></script>
</head>
<body class="Element700" onload="onBodyLoadEx('systemverilog31a.html', 'topic', '00530.html');" onmousedown="onBodyMouseDown();">

<!-- Begin Popups -->
<div class="Element801" id="popup00066">
<div class="Element800">
<div class="Element14">
链接</div>
<div class="Element11">
<div class="Element10">
<a href="00874.html" target="topic">第四章 数组</a></div>
</div>
</div>
</div>

<!-- End Popups -->

<!-- Begin Page Header -->
<div class="Element710" id="areafixed">
<div class="Element92">
<table width="100%" cellspacing="0" cellpadding="0">
<tr><td width="33%">
<div class="Element1">
<a href="#" onmousedown="showPopup(this, 'popup00066');"><img src="seealsolink.png" border="0" alt="" title=""></a> SystemVerilog 3.1a语言参考手册</div>
</td><td width="34%">
<div class="Element2">
</div>
</td><td width="33%">
<div class="Element90">
<a href="00529.html" target="topic"><img src="btn_prev_lightblue.gif" border="0" alt="Previous" title="Previous" onmouseover="switchImage(this, 'btn_prev_lightblue_hover.gif');" onmouseout="switchImage(this, 'btn_prev_lightblue.gif');"></a><a href="00874.html" target="topic"><img src="btn_up_lightblue.gif" border="0" alt="Up" title="Up" onmouseover="switchImage(this, 'btn_up_lightblue_hover.gif');" onmouseout="switchImage(this, 'btn_up_lightblue.gif');"></a><a href="00531.html" target="topic"><img src="btn_next_lightblue.gif" border="0" alt="Next" title="Next" onmouseover="switchImage(this, 'btn_next_lightblue_hover.gif');" onmouseout="switchImage(this, 'btn_next_lightblue.gif');"></a></div>
</td></tr></table><div class="Element5">
4.7 数组赋值</div>
</div>
</div>

<!-- End Page Header -->

<!-- Begin Client Area -->
<div class="Element720" id="areascroll">
<div class="Element721">

<!-- Begin Page Content -->
<div class="Element58">
<a name="描述"></a><div class="Element11">
<div class="Element10">
<p class="Element10">
对固定尺寸的非压缩数组赋值要求源数组和目的数组都具有相同非压缩维数，并且每一维的长度都必须相同。赋值通过将源数组的每一个元素赋值给目的数组的对应元素来实现，它要求源数组与目的数组具有兼容的类型。兼容类型是指在赋值操作上能够兼容的类型。在尺寸不等的固定尺寸非压缩数组间赋值会导致类型检查错误。 </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00126');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00126"><pre class="Element12"><span style="color: #0000FF">int</span> A<span style="color: #800080">[</span><span style="color: #FF0000">10</span><span style="color: #800080">:</span><span style="color: #FF0000">1</span><span style="color: #800080">];</span> <span style="color: #008000">// 具有10个元素的固定尺寸数组</span>
<span style="color: #0000FF">int</span> B<span style="color: #800080">[</span><span style="color: #FF0000">0</span><span style="color: #800080">:</span><span style="color: #FF0000">9</span><span style="color: #800080">];</span>  <span style="color: #008000">// 具有10个元素的固定尺寸数组</span>
<span style="color: #0000FF">int</span> C<span style="color: #800080">[</span><span style="color: #FF0000">24</span><span style="color: #800080">:</span><span style="color: #FF0000">1</span><span style="color: #800080">];</span> <span style="color: #008000">// 具有24个元素的固定尺寸数组</span>
A <span style="color: #800080">=</span> B<span style="color: #800080">;</span>       <span style="color: #008000">// 正确。兼容类型并具有相同的尺寸</span>
A <span style="color: #800080">=</span> C<span style="color: #800080">;</span>       <span style="color: #008000">// 类型检查错误：不同的尺寸</span></pre></div></div>
<p class="Element10">
<span style="color: #0000FF">wire</span>数组可以赋值为具有相同的非压缩维数并且每一维都具有相同长度的变量数组，反之亦然。 </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00127');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00127"><pre class="Element12"><span style="color: #0000FF">wire</span> <span style="color: #800080">[</span><span style="color: #FF0000">31</span><span style="color: #800080">:</span><span style="color: #FF0000">0</span><span style="color: #800080">]</span> W<span style="color: #800080">[</span><span style="color: #FF0000">9</span><span style="color: #800080">:</span><span style="color: #FF0000">0</span><span style="color: #800080">];</span>
<span style="color: #0000FF">assign</span> W <span style="color: #800080">=</span> A<span style="color: #800080">;</span>
<span style="color: #0000FF">initial</span> <span style="color: #800080">#</span><span style="color: #FF0000">10</span> B = W<span style="color: #800080">;</span></pre></div></div>
<p class="Element10">
如果一个动态数组与一个固定尺寸数组维数的长度相同，那么这个动态数组可以被赋值为一个具有兼容类型的一维固定尺寸数组。与固定尺寸数组的赋值不同，这个操作在运行时进行类型检查，这可能会导致一个错误。 </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00128');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00128"><pre class="Element12"><span style="color: #0000FF">int</span> A<span style="color: #800080">[</span><span style="color: #FF0000">100</span><span style="color: #800080">:</span><span style="color: #FF0000">1</span><span style="color: #800080">];</span>       <span style="color: #008000">// 具有100个元素的固定尺寸数组</span>
<span style="color: #0000FF">int</span> B<span style="color: #800080">[] =</span> <span style="color: #0000FF">new</span><span style="color: #800080">[</span><span style="color: #FF0000">100</span><span style="color: #800080">];</span> <span style="color: #008000">// 具有100个元素的动态数组</span>
<span style="color: #0000FF">int</span> C<span style="color: #800080">[] =</span> <span style="color: #0000FF">new</span><span style="color: #800080">[</span><span style="color: #FF0000">8</span><span style="color: #800080">];</span>   <span style="color: #008000">// 具有8个元素的动态数组</span>
A <span style="color: #800080">=</span> B<span style="color: #800080">;</span>              // <span style="color: #008000">兼容类型并具有相同的尺寸</span>
A <span style="color: #800080">=</span> C<span style="color: #800080">;</span>              <span style="color: #008000">// 类型检查错误：不同的尺寸</span></pre></div></div>
<p class="Element10">
一个动态数组或一维固定尺寸数组可以被赋值到一个具有兼容类型的动态数组。在这种情况下，赋值会产生一个新的动态数组，这个新的动态数组的长度等于固定尺寸数组的长度。例如： </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00129');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00129"><pre class="Element12"><span style="color: #0000FF">int</span> A<span style="color: #800080">[</span><span style="color: #FF0000">100</span><span style="color: #800080">:</span><span style="color: #FF0000">1</span><span style="color: #800080">];</span>     <span style="color: #008000">// 具有100个元素的固定尺寸数组</span>
<span style="color: #0000FF">int</span> B<span style="color: #800080">[];</span>          <span style="color: #008000">// 空的动态数组</span>
<span style="color: #0000FF">int</span> C<span style="color: #800080">[] =</span> <span style="color: #0000FF">new</span><span style="color: #800080">[</span><span style="color: #FF0000">8</span><span style="color: #800080">];</span> <span style="color: #008000">// 具有8个元素的动态数组</span>
B <span style="color: #800080">=</span> A<span style="color: #800080">;</span>            <span style="color: #008000">// 正确，B具有100个元素</span>
B <span style="color: #800080">=</span> C<span style="color: #800080">;</span>            <span style="color: #008000">// 正确，B具有8个元素</span></pre></div></div>
<p class="Element10">
最后一条语句等价于： </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00130');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00130"><pre class="Element12">B <span style="color: #800080">=</span> <span style="color: #0000FF">new</span><span style="color: #800080">[</span>C<span style="color: #800080">.</span><span style="color: #0000FF">size</span><span style="color: #800080">](</span>C<span style="color: #800080">);</span></pre></div></div>
<p class="Element10">
相似地，赋值的源可以是一个调用数组分片或串联的复杂表达式。例如： </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00131');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00131"><pre class="Element12"><span style="color: #0000FF">string</span> d<span style="color: #800080">[</span><span style="color: #FF0000">1</span><span style="color: #800080">:</span><span style="color: #FF0000">5</span><span style="color: #800080">] = {</span><span style="color: #575D94">&quot;a&quot;</span><span style="color: #800080">,</span> <span style="color: #575D94">&quot;b&quot;</span><span style="color: #800080">,</span> <span style="color: #575D94">&quot;c&quot;</span><span style="color: #800080">,</span> <span style="color: #575D94">&quot;d&quot;</span><span style="color: #800080">,</span> <span style="color: #575D94">&quot;e&quot;</span><span style="color: #800080">};</span>
<span style="color: #0000FF">string</span> p<span style="color: #800080">[];</span>
p <span style="color: #800080">= {</span>d<span style="color: #800080">[</span><span style="color: #FF0000">1</span><span style="color: #800080">:</span><span style="color: #FF0000">3</span><span style="color: #800080">],</span> <span style="color: #575D94">&quot;hello&quot;</span><span style="color: #800080">,</span> d<span style="color: #800080">[</span><span style="color: #FF0000">4</span><span style="color: #800080">:</span><span style="color: #FF0000">5</span><span style="color: #800080">]};</span></pre></div></div>
<p class="Element10">
上面的例子产生动态数组<i>p</i>，并具有<i>“a”, “b”, “c”, “hello”, “d”, “e”</i>的内容。</p></div>
</div>
<a name="Group"></a><div class="Element14">
<a onclick="toggleVisibilityStored('Group');" class="a_Element14"><img src="sectionminus.png" border="0" alt="" title="" id="imgGroup">Group</a></div>
<div id="divGroup">
<div class="Element11">
<div class="Element10">
<p class="Element10">
<a href="00874.html" target="topic">第四章 数组</a></p></div>
</div>
</div>
<a name="Links"></a><div class="Element14">
<a onclick="toggleVisibilityStored('链接');" class="a_Element14"><img src="sectionminus.png" border="0" alt="" title="" id="img链接">链接</a></div>
<div id="div链接">
<div class="Element11">
<div class="Element10">
<a href="00874.html" target="topic">第四章 数组</a></div>
</div>
</div>
</div>
<!-- End Page Content -->

<!-- Begin Page Footer -->
<hr width="98%" align="center" size="1" color="#CCCCCC" />
<table align="center" cellpadding="0" cellspacing="0" border="0">
	<tbody>
		<tr height="10">
			<td></td>
		</tr>
		<tr align="center">
			<td>
<script type="text/javascript"><!--
google_ad_client = "pub-5266859600380184";
google_ad_width = 468;
google_ad_height = 60;
google_ad_format = "468x60_as";
google_ad_type = "text_image";
google_ad_channel ="";
google_page_url = document.location;
//--></script>
<script type="text/javascript"
  src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
</script>
			</td>
		</tr>
		<tr height="15">
			<td></td>
		</tr>
		<tr align="center">
			<td>
				<font size=2>除非特别声明，原文版权归作者所有，如有转摘请注明原作者以及译者（<a href="http://www.fpgatech.net/"  target="_blank">FPGA技术网</a>）信息。<br />
如果您对本主题有何建议或意见，请登陆<a href="http://www.fpgatech.net/forum/forumdisplay.php?fid=18" target="_blank">FPGA开发者家园</a>提交，您的参与是我们前进的动力。</font>
<script language="javascript" type="text/javascript" src="http://js.users.51.la/195685.js"></script>
<noscript><a href="http://www.51.la/?195685" target="_blank"><img alt="&#x6211;&#x8981;&#x5566;&#x514D;&#x8D39;&#x7EDF;&#x8BA1;" src="http://img.users.51.la/195685.asp" style="border:none" /></a></noscript>
			</td>
		</tr>
	</tbody>
</table>

<!-- End Page Footer -->
</div>
</div>

<!-- End Client Area -->
</body></html>

⌨️ 快捷键说明

复制代码 Ctrl + C
搜索代码 Ctrl + F
全屏模式 F11
切换主题 Ctrl + Shift + D
显示快捷键 ?
增大字号 Ctrl + =
减小字号 Ctrl + -