c-over4.html

vxworks相关论文

<dd><p class="Body"><a name="83737"> </a>The library <b class="library">lstLib</b> contains a complete set of routines for creating and manipulating doubly-linked lists.</p>
</dl>

<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="83739">ANSI C Libraries</a></i></h5>
</font><dl class="margin">

<dd><p class="Body"><a name="83740"> </a>VxWorks provides all C libraries specified by ANSI X3.159-1989. The ANSI C specification includes the following libraries: <b class="library">assert</b>, <b class="library">ctype</b>,<b class="library"> errno</b>, <b class="library">float</b>,<b class="library"> limits</b>, <b class="library">locale</b>, <b class="library">math</b>,<b class="library"> setjmp</b>,<b class="library"> signal</b>,<b class="library"> stdarg</b>,<b class="library"> stdio</b>, <b class="library">stddef</b>, <b class="library">stdlib</b>, <b class="library">string</b>, and<b class="library"> time</b>.</p>
<dd><p class="Body"><a name="83741"> </a>The header files <b class="file">float.h</b>, <b class="file">limits.h</b>,<b class="file"> errno.h</b>, and <b class="file">stddef.h</b> provide ANSI-specified definitions and declarations. The more commonly used libraries are described in the following reference entries:<p class="table">
<table border="0" cellpadding="0" cellspacing="0">
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="86518"> </a><b class="library">ansiCtype</b> </p>

</td>

<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="86520"> </a>routines for character manipulation </p>

</td>


</tr>
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="87355"> </a><b class="library">ansiMath</b> </p>

</td>

<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="86524"> </a>trigonometric, exponential, and logarithmic routines </p>

</td>


</tr>
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="86526"> </a><b class="library">ansiSetjmp</b> </p>

</td>

<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="86528"> </a>routines for implementing a non-local goto </p>

</td>


</tr>
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="86530"> </a><b class="library">ansiStdarg</b> </p>

</td>

<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="86532"> </a>routines for traversing a variable-length argument list </p>

</td>


</tr>
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="86534"> </a><b class="library">ansiStdio</b> </p>

</td>

<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="86536"> </a>routines for manipulating streams for input/output </p>

</td>


</tr>
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="86538"> </a><b class="library">ansiStdlib</b> </p>

</td>

<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="86540"> </a>a variety of routines, including those for type translation, memory allocation, and random number generation </p>

</td>


</tr>
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="86542"> </a><b class="library">sigLib</b> </p>

</td>

<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="86544"> </a>signal-manipulation routines </p>

</td>


</tr>

<tr valign="middle">
<td colspan="20">

</td>
</tr>
</table>
</p>
</p>
</dl>

</dl>

<font face="Helvetica, sans-serif" class="sans">
<h4 class="H4"><i><a name="83765">Performance Evaluation</a></i></h4>
</font>
<dl class="margin">

<dl class="margin">

<dd><p class="Body"><a name="83767"> </a>To understand and optimize the performance of a real-time system, it can be useful to time some of the VxWorks or application routines. VxWorks provides various timing facilities to help with this task.</p>
<dd><p class="Body"><a name="83769"> </a>The VxWorks execution timer can time any subroutine or group of subroutines. Because the system clock is too slow to provide the resolution necessary to time especially fast routines, the timer can also repeatedly execute a group of routines until the time of a single iteration is known to a reasonable accuracy. For information on the execution timer, see the <b class="library">timexLib</b> reference entry.</p>
<dd><p class="Body"><a name="83771"> </a>VxWorks also provides the <i class="term">spy</i> utility, which provides CPU utilization information for each task: the CPU time consumed, the time spent at interrupt level, and the amount of idle time. Time is displayed in ticks and in percentages. For information on this utility, see the <b class="library">spyLib</b> reference entry.<sup><a href="#foot"><b class="FootnoteMarker">2</b></a></sup>
</p>
<dd><p class="Body"><a name="83775"> </a>Even more powerful monitoring of the VxWorks system is available using the optional product WindView; for more information, see the <i class="title">WindView User's Guide</i>. </p>
</dl>

</dl>

<font face="Helvetica, sans-serif" class="sans">
<h4 class="H4"><i><a name="83777">Target Agent</a></i></h4>
</font>
<dl class="margin">

<dl class="margin">

<dd><p class="Body"><a name="83779"> </a>The <i class="term">target agent</i> follows the WDB (Wind DeBug) protocol, allowing a VxWorks target to be connected to the Tornado development tools. In the target agent's default configuration, shown in <a href="c-over4.html#86473">Figure&nbsp;1-1</a>, the agent runs as the VxWorks task <b class="task">tWdbTask</b>. The Tornado target server sends debugging requests to the target agent. The debugging requests often result in the target agent controlling or manipulating other tasks in the system.</p>
<dd><p class="Body"><a name="83827"> </a>By default, the target server and agent communicate using the network. However, you can use alternative communication paths. For more information on the default configuration or alternative configurations of the target agent, see <i class="title">Tornado Getting Started. </i>For information on the Tornado target server, see the <i class="title">Tornado User's Guide: Overview</i>.<div class="frame">
<h4 class="EntityTitle"><a name="86473"><font face="Helvetica, sans-serif" size="-1" class="sans">Figure 1-1:&nbsp;&nbsp;Interaction Between Target Server and Target Agent</font></a></h4>

<dl class="margin">

<div class="Anchor"><a name="86512"> </a><img class="figure" border="0" src="images/c-overa.gif">
</div>



</dl>

</div>
</p>
</dl>

</dl>

<font face="Helvetica, sans-serif" class="sans">
<h4 class="H4"><i><a name="83830">Board Support Packages (BSPs)</a></i></h4>
</font>
<dl class="margin">

<dl class="margin">

<dd><p class="Body"><a name="83832"> </a><b></b>Two target-specific libraries, <b class="library">sysLib</b> and <b class="library">sysALib</b>, are included with each port of VxWorks. These libraries are the heart of VxWorks portability; they provide an identical software interface to the hardware functions of all boards. They include facilities for hardware initialization, interrupt handling and generation, hardware clock and timer management, mapping of local and bus memory spaces, memory sizing, and so on.</p>
<dd><p class="Body"><a name="83833"> </a>Each BSP also includes a boot ROM or other boot mechanism. Many of these import the run-time image from the development host. For information on boot ROMs and other booting mechanisms see <i class="title">Tornado Getting Started</i> and <a href="c-config9.html#86670"><i class="title">8.9&nbsp;Creating Bootable Applications</i></a>.</p>
<dd><p class="Body"><a name="83836"> </a>For information on target-specific libraries, see <a href="c-config2.html#87032"><i class="title">8.2&nbsp;The Board Support Package (BSP)</i></a> and the target-specific reference entries for your board type.</p>
</dl>

</dl>

<font face="Helvetica, sans-serif" class="sans">
<h4 class="H4"><i><a name="83839">VxWorks Simulator </a></i></h4>
</font>
<dl class="margin">

<dl class="margin">

<dd><p class="Body"><a name="83840"> </a>VxSim, the VxWorks simulator, is a program that simulates a VxWorks target for use as a prototyping and testing environment. The integrated version of the simulator allows a single simulator to be run. The VxSim optional product adds networking facilities, allowing the simulator to obtain an Internet address and communicate with the host (or other nodes on the network) using the VxWorks networking tools.</p>
<dd><p class="Body"><a name="83841"> </a>VxSim is essentially a port of VxWorks. In most regards, its capabilities are identical to a true VxWorks system running on remote target hardware. You can link in an application and rebuild the VxWorks image exactly the same way as in any other VxWorks cross-development environment. All Tornado development tools can be used with VxSim.</p>
<dd><p class="Body"><a name="83842"> </a>The difference between VxSim and a remote VxWorks target environment is that in VxSim, the image executes on the host machine itself as a host process. There is no emulation of instructions, because the code is in the host's own CPU architecture. Because target hardware interaction is not possible, device-driver development may not be suitable for simulation. However, the VxWorks scheduler is implemented in the VxSim process, maintaining true tasking interaction with respect to priorities and preemption. This means that any application that is written in a portable style and with minimal hardware interaction should be portable between VxSim and VxWorks.</p>
<dd><p class="Body"><a name="83845"> </a>For more information on VxSim, see <a href="x-vxsim.html#84367"><i class="title">H.&nbsp;VxSim</i></a>.</p>
</dl>

</dl>


<a name="foot"><hr></a>

<p class="FootnoteNumberMarker">1:&nbsp;
<span class="Footnote"><a name="86769"> </a><i class="term">BSD</i> stands for Berkeley Software Distribution, and refers to a version of UNIX.</span>
<p class="FootnoteNumberMarker">2:&nbsp;
<span class="Footnote"><a name="83774"> </a>You can also use this utility through the Tornado browser; see the <i class="title">Tornado User's Guide: Browser </i>for details.</span>

<p class="navbar" align="right"><a href="index.html"><img border="0" alt="[Contents]" src="icons/contents.gif"></a><a href="GuideIX.html"><img border="0" alt="[Index]" src="icons/index.gif"></a><a href="c-over.html"><img border="0" alt="[Top]" src="icons/top.gif"></a><a href="c-over3.html"><img border="0" alt="[Prev]" src="icons/prev.gif"></a><a href="c-over5.html"><img border="0" alt="[Next]" src="icons/next.gif"></a></p>

</body>

</html>
<!---
by WRS Documentation (), Wind River Systems, Inc.
    conversion tool:  Quadralay WebWorks Publisher 4.0.11
    template:         CSS Template, Jan 1998 - Jefro --->