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<?xml version="1.0" encoding="gb2312"?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=gb2312"/><title>linux for ppc chapter 4                jacobw </title></head><body><center><h1>BBS 水木清华站∶精华区</h1></center><a name="top"></a>发信人:&nbsp;plato&nbsp;(纯真年代),&nbsp;信区:&nbsp;Embedded&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />标&nbsp;&nbsp;题:&nbsp;linux&nbsp;for&nbsp;ppc&nbsp;chapter&nbsp;4&nbsp;<br />发信站:&nbsp;BBS&nbsp;水木清华站&nbsp;(Wed&nbsp;May&nbsp;30&nbsp;23:10:16&nbsp;2001)&nbsp;<br />&nbsp;<br />Next&nbsp;Previous&nbsp;Contents&nbsp;<br />----------------------------------------------------------------------------&nbsp;<br />----&nbsp;<br />4.&nbsp;Host&nbsp;Development&nbsp;Platform&nbsp;<br />Embedded&nbsp;Linux's&nbsp;compelling&nbsp;advantage&nbsp;over&nbsp;other&nbsp;Embedded&nbsp;OS's&nbsp;is&nbsp;that&nbsp;your&nbsp;&nbsp;<br />development&nbsp;host&nbsp;and&nbsp;target&nbsp;are&nbsp;the&nbsp;same.&nbsp;While&nbsp;you&nbsp;could&nbsp;theoretically&nbsp;deve&nbsp;<br />lop&nbsp;your&nbsp;embedded&nbsp;Linux&nbsp;target&nbsp;system&nbsp;software&nbsp;on&nbsp;any&nbsp;host&nbsp;OS,&nbsp;Linux&nbsp;is&nbsp;the&nbsp;&nbsp;<br />only&nbsp;sensible&nbsp;choice.&nbsp;Even&nbsp;Cygwin/UWIN&nbsp;is&nbsp;likely&nbsp;to&nbsp;waste&nbsp;more&nbsp;of&nbsp;your&nbsp;time.&nbsp;<br />&nbsp;<br />4.1&nbsp;PowerPC&nbsp;<br />Using&nbsp;a&nbsp;PowerPC&nbsp;based&nbsp;development&nbsp;development&nbsp;host&nbsp;platform&nbsp;makes&nbsp;life&nbsp;easie&nbsp;<br />r,&nbsp;since&nbsp;the&nbsp;same&nbsp;binaries&nbsp;will&nbsp;run&nbsp;on&nbsp;your&nbsp;host&nbsp;and&nbsp;target.&nbsp;However,&nbsp;if&nbsp;you&nbsp;<br />r&nbsp;choice&nbsp;of&nbsp;host&nbsp;platform&nbsp;is&nbsp;restricted&nbsp;to&nbsp;non-PowerPC,&nbsp;cross&nbsp;compiling&nbsp;adds&nbsp;<br />&nbsp;some&nbsp;minor&nbsp;inconvenience,&nbsp;primarily&nbsp;in&nbsp;finding&nbsp;or&nbsp;building&nbsp;your&nbsp;own&nbsp;toolset&nbsp;<br />.&nbsp;<br />You&nbsp;can&nbsp;take&nbsp;binaries&nbsp;from&nbsp;a&nbsp;standard&nbsp;PowerPC-based&nbsp;G4&nbsp;Macintosh&nbsp;Linux&nbsp;distr&nbsp;<br />ibution&nbsp;and&nbsp;run&nbsp;them&nbsp;unmodified&nbsp;on&nbsp;a&nbsp;PowerPC&nbsp;embedded&nbsp;system&nbsp;provided:&nbsp;<br />The&nbsp;binaries&nbsp;are&nbsp;dynamically&nbsp;linked.&nbsp;<br />You&nbsp;use&nbsp;the&nbsp;modified&nbsp;dynamic&nbsp;runtime&nbsp;glibc&nbsp;C&nbsp;library,&nbsp;but&nbsp;compiled&nbsp;with&nbsp;-mha&nbsp;<br />rd-float.&nbsp;<br />You&nbsp;include&nbsp;the&nbsp;floating&nbsp;point&nbsp;math&nbsp;emulator&nbsp;in&nbsp;the&nbsp;kernel&nbsp;for&nbsp;processors&nbsp;su&nbsp;<br />ch&nbsp;as&nbsp;the&nbsp;8xx&nbsp;series&nbsp;that&nbsp;lack&nbsp;a&nbsp;real&nbsp;floating&nbsp;point&nbsp;unit.&nbsp;<br />Note&nbsp;that&nbsp;for&nbsp;floating-point&nbsp;intensive&nbsp;applications&nbsp;this&nbsp;will&nbsp;invoke&nbsp;a&nbsp;perfo&nbsp;<br />rmance&nbsp;penalty&nbsp;over&nbsp;re-compiling&nbsp;all&nbsp;the&nbsp;binaries&nbsp;and&nbsp;libraries;&nbsp;but&nbsp;recompi&nbsp;<br />ling&nbsp;is&nbsp;what&nbsp;you're&nbsp;trying&nbsp;to&nbsp;avoid,&nbsp;right?&nbsp;<br />Also&nbsp;note&nbsp;that&nbsp;standard&nbsp;Macintosh&nbsp;binaries&nbsp;won't&nbsp;work&nbsp;with&nbsp;the&nbsp;runtime&nbsp;libra&nbsp;<br />ry&nbsp;in&nbsp;the&nbsp;Hard&nbsp;Hat&nbsp;distribution&nbsp;on&nbsp;8xx&nbsp;processors,&nbsp;because&nbsp;they've&nbsp;been&nbsp;comp&nbsp;<br />iled&nbsp;with&nbsp;-msoft-float&nbsp;to&nbsp;give&nbsp;optimum&nbsp;performance.&nbsp;In&nbsp;this&nbsp;case&nbsp;just&nbsp;use&nbsp;th&nbsp;<br />e&nbsp;equivalent&nbsp;Hard&nbsp;Hat&nbsp;binaries&nbsp;instead.&nbsp;<br />4.2&nbsp;x86&nbsp;<br />Doing&nbsp;it&nbsp;this&nbsp;way&nbsp;is&nbsp;slightly&nbsp;more&nbsp;painful,&nbsp;but&nbsp;it's&nbsp;what&nbsp;most&nbsp;people&nbsp;use.&nbsp;<br />----------------------------------------------------------------------------&nbsp;<br />----&nbsp;<br />Next&nbsp;Previous&nbsp;Contents&nbsp;&nbsp;<br />&nbsp;<br />--&nbsp;<br />&nbsp;<br />※&nbsp;来源:·BBS&nbsp;水木清华站&nbsp;smth.org·[FROM:&nbsp;166.111.161.8]&nbsp;<br /><a href="00000003.htm">上一篇</a><a href="javascript:history.go(-1)">返回上一页</a><a href="index.htm">回到目录</a><a href="#top">回到页首</a><a href="00000005.htm">下一篇</a></h1></center><center><h1>BBS 水木清华站∶精华区</h1></center></body></html>
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