Sun, 01 Nov 2009 09:36:00 GMTCSDN博客聚合服务http://blog.csdn.net/blogrss.aspx?username=feijj2002_http://blog.csdn.net/feijj2002_/archive/2009/11/01/4754725.aspxhttp://download.csdn.net/source/1786950 下载<img src="http://www1.feedsky.com/t1/290588734/feijj2002_/csdn.net/s.gif?r=http://blog.csdn.net/feijj2002_/archive/2009/11/01/4754725.aspx" border="0" height="0" width="0" style="position:absolute" /><p class="fswww1"><a href="http://www1.feedsky.com/r/l/csdn.net/feijj2002_/290588734/art01.html" target="_blank"><img border="0" ismap="ismap" src="http://www1.feedsky.com/r/i/csdn.net/feijj2002_/290588734/art01.gif" onerror="this.style.display='none'" /></a></p>Sun, 01 Nov 2009 17:36:00 +0800feijj2002_http://blog.csdn.net/feijj2002_/archive/2009/11/01/4754725.aspxfeijj2002_http://blog.csdn.net/feijj2002_/archive/2009/11/01/4754725.aspxhttp://blog.csdn.net/feijj2002_/feed.aspxcsdn.net/feijj2002_/~1130107/290588734/1130101http://blog.csdn.net/feijj2002_/archive/2009/09/26/4597174.aspx之所以出现这个定义是因为系统要安全:内核要和用户程序分开..内核一定要安全.不能被用户程序干涉.但是有时候用户程序也需要读取内核的某些数据,怎么办呢?操作系统就引入了访问特权等级(0-3)的机制.这些特权等级,通过三个符号来体现CPL\DPL\RPL.其中CPL是存寄存器如CS中,RPL是代码中根据不同段跳转而确定,以动态刷新CS里的CPL.DPL是在GDT/LDT描述符表中,静态的。1.在x86中的数据和代码是按段来存放的:[section],GTL\LDT里的每个段描述符被设置有不同的特权级DPL.2.程序是通过选择子/门调用等等来在段之间来回走动的.实现用户级与系统级的调用跳转.3.与GDT里的段描述符一样，CPU寄存器内的每一个选择子/门调用选择子是有分等级的:这个是在选择符的结构中:RPL(最后2位)调用的选择符和被调用的段都分了等级.那么这些等级在调用时按什么规则实现跳转呢?<img src="http://www1.feedsky.com/t1/290588735/feijj2002_/csdn.net/s.gif?r=http://blog.csdn.net/feijj2002_/archive/2009/09/26/4597174.aspx" border="0" height="0" width="0" style="position:absolute" /><p class="fswww1"><a href="http://www1.feedsky.com/r/l/csdn.net/feijj2002_/290588735/art01.html" target="_blank"><img border="0" ismap="ismap" src="http://www1.feedsky.com/r/i/csdn.net/feijj2002_/290588735/art01.gif" onerror="this.style.display='none'" /></a></p>Sat, 26 Sep 2009 13:56:00 +0800feijj2002_http://blog.csdn.net/feijj2002_/archive/2009/09/26/4597174.aspxfeijj2002_http://blog.csdn.net/feijj2002_/archive/2009/09/26/4597174.aspxhttp://blog.csdn.net/feijj2002_/feed.aspxcsdn.net/feijj2002_/~1130107/290588735/1130101http://blog.csdn.net/feijj2002_/archive/2009/04/13/4068775.aspx汉语，分开说就是“汉字”和“语言”。 汉字，古人都认为书画同源。 也就是在约公元前14世纪的殷商后期的金文、铭文和甲骨文，它们是中国最早的文字，字也是画，画也是字，即象形文字。 ­象形文字，是用来表意的，如“日”，表示太阳，但表音很弱，最处的文字都有一个读音，但随着文字的发展，文字增多，文字注音也变得越来越复杂。（可能因各地方言不一样，难以统一）汉字以本身表义为主（所以表达力很强），注音方面较为薄弱（以至对汉字不容易学习掌握推广）。不象拉丁字母组成的英语，为拼音文字，字母少，既表义又表音，会写就会读。 而汉字，表音和表义是分开的。 ­最早的汉字注音法有：读若法和直注法。读若法就是用音近的字来注音（也就是用已有标准读音的汉字为新汉字注音），许慎的《说文解字》就采用这种注音方法，如“埻，射臬也，读若准”。直注法就是用另一个汉字来表明这个汉字的读音，如“女为说己者容”中，使用“说者曰悦”来进行注音。 ­魏晋时期发展出了反切法，即用两个基本汉字为一个新汉字的注音。即用第一个基本汉字的声母和第二个基本汉字的韵母和声调合拼来注音，使得所有汉字发音都有可能组合出来。如“练，朗甸切”，即“练”的发音是<p class="fswww1"><a href="http://www1.feedsky.com/r/l/csdn.net/feijj2002_/290588736/art01.html" target="_blank"><img border="0" ismap="ismap" src="http://www1.feedsky.com/r/i/csdn.net/feijj2002_/290588736/art01.gif" onerror="this.style.display='none'" /></a></p>Mon, 13 Apr 2009 11:39:00 +0800feijj2002_http://blog.csdn.net/feijj2002_/archive/2009/04/13/4068775.aspxfeijj2002_http://blog.csdn.net/feijj2002_/archive/2009/04/13/4068775.aspxhttp://blog.csdn.net/feijj2002_/feed.aspxcsdn.net/feijj2002_/~1130107/290588736/1130101http://blog.csdn.net/feijj2002_/archive/2007/08/05/1727228.aspx.<p class="fswww1"><a href="http://www1.feedsky.com/r/l/csdn.net/feijj2002_/290588737/art01.html" target="_blank"><img border="0" ismap="ismap" src="http://www1.feedsky.com/r/i/csdn.net/feijj2002_/290588737/art01.gif" onerror="this.style.display='none'" /></a></p>Sun, 05 Aug 2007 18:26:00 +0800feijj2002_http://blog.csdn.net/feijj2002_/archive/2007/08/05/1727228.aspxfeijj2002_http://blog.csdn.net/feijj2002_/archive/2007/08/05/1727228.aspxhttp://blog.csdn.net/feijj2002_/feed.aspxcsdn.net/feijj2002_/~1130107/290588737/1130101http://blog.csdn.net/feijj2002_/archive/2007/08/05/1727206.aspx.<p class="fswww1"><a href="http://www1.feedsky.com/r/l/csdn.net/feijj2002_/290588738/art01.html" target="_blank"><img border="0" ismap="ismap" src="http://www1.feedsky.com/r/i/csdn.net/feijj2002_/290588738/art01.gif" onerror="this.style.display='none'" /></a></p>Sun, 05 Aug 2007 18:16:00 +0800feijj2002_http://blog.csdn.net/feijj2002_/archive/2007/08/05/1727206.aspxfeijj2002_http://blog.csdn.net/feijj2002_/archive/2007/08/05/1727206.aspxhttp://blog.csdn.net/feijj2002_/feed.aspxcsdn.net/feijj2002_/~1130107/290588738/1130101http://blog.csdn.net/feijj2002_/archive/2007/08/03/1723688.aspx.<p class="fswww1"><a href="http://www1.feedsky.com/r/l/csdn.net/feijj2002_/290588739/art01.html" 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+0800feijj2002_http://blog.csdn.net/feijj2002_/archive/2007/06/26/1667754.aspxfeijj2002_http://blog.csdn.net/feijj2002_/archive/2007/06/26/1667754.aspxhttp://blog.csdn.net/feijj2002_/feed.aspxcsdn.net/feijj2002_/~1130107/290588740/1130101http://blog.csdn.net/feijj2002_/archive/2007/06/22/1662484.aspx.<p class="fswww1"><a href="http://www1.feedsky.com/r/l/csdn.net/feijj2002_/290588741/art01.html" target="_blank"><img border="0" ismap="ismap" src="http://www1.feedsky.com/r/i/csdn.net/feijj2002_/290588741/art01.gif" onerror="this.style.display='none'" /></a></p>Fri, 22 Jun 2007 20:46:00 +0800feijj2002_http://blog.csdn.net/feijj2002_/archive/2007/06/22/1662484.aspxfeijj2002_http://blog.csdn.net/feijj2002_/archive/2007/06/22/1662484.aspxhttp://blog.csdn.net/feijj2002_/feed.aspxcsdn.net/feijj2002_/~1130107/290588741/1130101http://blog.csdn.net/feijj2002_/archive/2007/06/10/1647233.aspx.<p class="fswww1"><a href="http://www1.feedsky.com/r/l/csdn.net/feijj2002_/290588742/art01.html" target="_blank"><img border="0" ismap="ismap" src="http://www1.feedsky.com/r/i/csdn.net/feijj2002_/290588742/art01.gif" onerror="this.style.display='none'" /></a></p>Sun, 10 Jun 2007 22:48:00 +0800feijj2002_http://blog.csdn.net/feijj2002_/archive/2007/06/10/1647233.aspxfeijj2002_http://blog.csdn.net/feijj2002_/archive/2007/06/10/1647233.aspxhttp://blog.csdn.net/feijj2002_/feed.aspxcsdn.net/feijj2002_/~1130107/290588742/1130101http://blog.csdn.net/feijj2002_/archive/2007/05/12/1606258.aspx.<p class="fswww1"><a href="http://www1.feedsky.com/r/l/csdn.net/feijj2002_/290588743/art01.html" target="_blank"><img border="0" ismap="ismap" src="http://www1.feedsky.com/r/i/csdn.net/feijj2002_/290588743/art01.gif" onerror="this.style.display='none'" /></a></p>Sat, 12 May 2007 20:29:00 +0800feijj2002_http://blog.csdn.net/feijj2002_/archive/2007/05/12/1606258.aspxfeijj2002_http://blog.csdn.net/feijj2002_/archive/2007/05/12/1606258.aspxhttp://blog.csdn.net/feijj2002_/feed.aspxcsdn.net/feijj2002_/~1130107/290588743/1130101