📄 第四章 keil c51高级编程.htm
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<P class=MsoNormal
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align=center><SPAN
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">双字节由<SPAN
lang=EN-US>R6和R7返回,MSB在R6<O:P></O:P></SPAN></SPAN></P></TD></TR>
<TR>
<TD
style="BORDER-RIGHT: windowtext 0.75pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 117pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.75pt solid; mso-border-top-alt: solid windowtext .75pt"
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<P class=MsoNormal
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align=center><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">long&unsigned
long <O:P></O:P></SPAN></P></TD>
<TD
style="BORDER-RIGHT: windowtext 0.75pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 79.85pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.75pt solid; mso-border-left-alt: solid windowtext .75pt; mso-border-top-alt: solid windowtext .75pt"
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<P class=MsoNormal
style="TEXT-ALIGN: center; tab-stops: 63.0pt"
align=center><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">R4～R7<O:P></O:P></SPAN></P></TD>
<TD
style="BORDER-RIGHT: medium none; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 196.85pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.75pt solid; mso-border-left-alt: solid windowtext .75pt; mso-border-top-alt: solid windowtext .75pt"
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<P class=MsoNormal
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align=center><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">MSB在R4,<SPAN
style="mso-spacerun: yes">
</SPAN>LSB在R7<O:P></O:P></SPAN></P></TD></TR>
<TR>
<TD
style="BORDER-RIGHT: windowtext 0.75pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 117pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.75pt solid; mso-border-top-alt: solid windowtext .75pt"
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<P class=MsoNormal
style="TEXT-ALIGN: center; tab-stops: 63.0pt"
align=center><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">float<O:P></O:P></SPAN></P></TD>
<TD
style="BORDER-RIGHT: windowtext 0.75pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 79.85pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.75pt solid; mso-border-left-alt: solid windowtext .75pt; mso-border-top-alt: solid windowtext .75pt"
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<P class=MsoNormal
style="TEXT-ALIGN: center; tab-stops: 63.0pt"
align=center><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">R4～R7<O:P></O:P></SPAN></P></TD>
<TD
style="BORDER-RIGHT: medium none; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 196.85pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.75pt solid; mso-border-left-alt: solid windowtext .75pt; mso-border-top-alt: solid windowtext .75pt"
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<P class=MsoNormal
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align=center><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">32Bit
IEEE格式</SPAN><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New Roman'"><O:P></O:P></SPAN></P></TD></TR>
<TR>
<TD
style="BORDER-RIGHT: windowtext 0.75pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 117pt; PADDING-TOP: 0cm; BORDER-BOTTOM: medium none; mso-border-top-alt: solid windowtext .75pt"
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<P class=MsoNormal
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align=center><SPAN
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">一般指针</SPAN><SPAN
lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New Roman'"><O:P></O:P></SPAN></P></TD>
<TD
style="BORDER-RIGHT: windowtext 0.75pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 79.85pt; PADDING-TOP: 0cm; BORDER-BOTTOM: medium none; mso-border-left-alt: solid windowtext .75pt; mso-border-top-alt: solid windowtext .75pt"
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<P class=MsoNormal
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align=center><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">R1～R3<O:P></O:P></SPAN></P></TD>
<TD
style="BORDER-RIGHT: medium none; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 196.85pt; PADDING-TOP: 0cm; BORDER-BOTTOM: medium none; mso-border-left-alt: solid windowtext .75pt; mso-border-top-alt: solid windowtext .75pt"
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<P class=MsoNormal
style="TEXT-ALIGN: center; tab-stops: 63.0pt"
align=center><SPAN
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">存储类型在<SPAN
lang=EN-US>R3 高位R2
低R1<O:P></O:P></SPAN></SPAN></P></TD></TR></TBODY></TABLE>
<P class=MsoNormal
style="TEXT-INDENT: 24pt; TEXT-ALIGN: left; tab-stops: 63.0pt"
align=left><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">(4) SRC控制</SPAN><SPAN
lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New Roman'"><O:P></O:P></SPAN></P>
<P class=MsoNormal
style="TEXT-INDENT: 24pt; TEXT-ALIGN: left; tab-stops: 63.0pt"
align=left><SPAN
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">该控制指令将<SPAN
lang=EN-US>C文件编译生成汇编文件(.SRC)，该汇编文件可改名后，生成汇编.ASM文件，再用A51进行编译。</SPAN></SPAN><SPAN
lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New Roman'"><O:P></O:P></SPAN></P>
<H2 style="MARGIN-LEFT: 0cm; TEXT-INDENT: 0cm"><A
name=_Toc475103190><SPAN lang=EN-US
style="FONT-SIZE: 16pt">第三节 </SPAN><SPAN lang=EN-US>Keil
C51软件包中的通用文件</SPAN></A></H2>
<P class=MsoBodyTextFirstIndent>在<SPAN
lang=EN-US>C51\LiB目录下有几个C源文件，这几个C源文件有非常重要的作用，对它们稍事修改，就可以用在自己的专用系统中。</SPAN></P>
<H3 style="MARGIN-LEFT: 0cm; TEXT-INDENT: 0cm"><A
name=_Toc475103191><SPAN lang=EN-US style="FONT-SIZE: 15pt">1.
</SPAN>动态内存分配</A></H3>
<P class=MsoNormal
style="MARGIN-LEFT: 90pt; TEXT-INDENT: -66pt; TEXT-ALIGN: left; tab-stops: 63.0pt"
align=left><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">init_mem.C：此文件是初始化动态内存区的程序源代码。它可以指定动态内存的位置及大小，只有使用了init_mem(
)才可以调回其它函数，诸如malloc calloc,realloc等。</SPAN><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New Roman'"><O:P></O:P></SPAN></P>
<P class=MsoNormal
style="MARGIN-LEFT: 90pt; TEXT-INDENT: -66pt; TEXT-ALIGN: left; tab-stops: 63.0pt"
align=left><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">calloc.c：此文件是给数组分配内存的源代码，它可以指定单位数据类型及该单元数目。</SPAN><SPAN
lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New Roman'"><O:P></O:P></SPAN></P>
<P class=MsoNormal
style="MARGIN-LEFT: 90pt; TEXT-INDENT: -66pt; TEXT-ALIGN: left; tab-stops: 63.0pt"
align=left><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">malloc.c：此文件是malloc的源代码，分配一段固定大小的内存。</SPAN><SPAN
lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New Roman'"><O:P></O:P></SPAN></P>
<P class=MsoNormal
style="MARGIN-LEFT: 90pt; TEXT-INDENT: -66pt; TEXT-ALIGN: left; tab-stops: 63.0pt"
align=left><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">realloc.c：此文件是realloc.c源代码，其功能是调整当前分配动态内存的大小。</SPAN><SPAN
lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New Roman'"><O:P></O:P></SPAN></P>
<H3 style="MARGIN-LEFT: 0cm; TEXT-INDENT: 0cm"><A
name=_Toc475103192><SPAN lang=EN-US style="FONT-SIZE: 15pt">2.
</SPAN><SPAN lang=EN-US>C51启动文件STARTUP.A51</SPAN></A></H3>
<P class=MsoBodyTextFirstIndent>启动文件<SPAN
lang=EN-US>STARTUP.A51中包含目标板启动代码，可在每个project中加入这个文件，只要复位，则该文件立即执行，其功能包括：</SPAN></P>
<P class=MsoNormal
style="MARGIN-LEFT: 45pt; TEXT-INDENT: -21pt; TEXT-ALIGN: left; tab-stops: list 45.0pt left 63.0pt; mso-list: l36 level1 lfo10"
align=left><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: Wingdings">l<SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN><SPAN
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">定义内部<SPAN
lang=EN-US>RAM大小、外部RAM大小、可重入堆栈位置</SPAN></SPAN><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New Roman'"><O:P></O:P></SPAN></P>
<P class=MsoNormal
style="MARGIN-LEFT: 45pt; TEXT-INDENT: -21pt; TEXT-ALIGN: left; tab-stops: list 45.0pt left 63.0pt; mso-list: l36 level1 lfo10"
align=left><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: Wingdings">l<SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN><SPAN
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">清除内部、外部或者以此页为单元的外部存储器</SPAN><SPAN
lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New Roman'"><O:P></O:P></SPAN></P>
<P class=MsoNormal
style="MARGIN-LEFT: 45pt; TEXT-INDENT: -21pt; TEXT-ALIGN: left; tab-stops: list 45.0pt left 63.0pt; mso-list: l36 level1 lfo10"
align=left><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: Wingdings">l<SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN><SPAN
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">按存储模式初使化重入堆栈及堆栈指针</SPAN><SPAN
lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New Roman'"><O:P></O:P></SPAN></P>
<P class=MsoNormal
style="MARGIN-LEFT: 45pt; TEXT-INDENT: -21pt; TEXT-ALIGN: left; tab-stops: list 45.0pt left 63.0pt; mso-list: l36 level1 lfo10"
align=left><SPAN lang=EN-US
style="FONT-SIZE: 12pt; FONT-FAMILY: Wingdings">l<SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN><SPAN
style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体">初始化<SPAN
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