📄 00776.html
字号:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN">
<html>
<head>
<title>E.6.6 Mapping between SystemVerilog ranges and normalized ranges</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', '00776.html');" onmousedown="onBodyMouseDown();">
<!-- Begin Popups -->
<div class="Element801" id="popup00785">
<div class="Element800">
<div class="Element14">
链接</div>
<div class="Element11">
<div class="Element10">
<a href="00770.html" target="topic">E.6 Data types</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, 'popup00785');"><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="00775.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="00770.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="00777.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">
E.6.6 Mapping between SystemVerilog ranges and normalized ranges</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">
The SystemVerilog ranges for a formal argument specified as an open array are those of the actual argument for a particular call. Open arrays are accessible, however, by using their original ranges and the same indexing as in the SystemVerilog code. </p>
<p class="Element10">
</p>
<p class="Element10">
For all other types of arguments, i.e., all arguments but open arrays, the SystemVerilog ranges are defined in the corresponding SystemVerilog import or export declaration. Normalized ranges are used for accessing such arguments in C code. The mapping between SystemVerilog ranges and normalized ranges is defined as follows.
<ol class="Element630">
<li value="1" class="Element600">If a packed part of an array has more than one dimension, it is linearized as specified by the equivalence of packed types (see Section 4.2).</li>
<li value="2" class="Element600">A packed array of range [L:R] is normalized as [abs(L-R):0]; its most significant bit has a normalized index abs(L-R) and its least significant bit has a normalized index 0.</li>
<li value="3" class="Element600">The natural order of elements for each dimension in the layout of an unpacked array shall be used, i.e., elements with lower indices go first. For SystemVerilog range [L:R], the element with SystemVerilog index min(L,R) has the C index 0 and the element with SystemVerilog index max(L,R) has the C index abs(L-R).</li>
</ol>NOTE—The above range mapping from SystemVerilog to C applies to calls made in both directions, i.e., SystemVerilogcalls to C and C-calls to SystemVerilog. </p>
<p class="Element10">
</p>
<p class="Element10">
For example, if logic [2:3][1:3][2:0] b [1:10] [31:0] is used in SystemVerilog, it needs to be defined in C as if it were declared in SystemVerilog in the following normalized form: logic [17:0] b[0:9] [0:31].</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="00770.html" target="topic">E.6 Data types</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="00770.html" target="topic">E.6 Data types</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="我要啦免费统计" 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 + -