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80x86汇编语言程序设计习题参考答案

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<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">3.8&nbsp; 
AX</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">的值将是返回地址的</font><font SIZE="3">16</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">位偏移地址。</p>
</font><font SIZE="3">
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">3.9 
</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">（</font><font SIZE="3">1</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">）除数为</font><font SIZE="3">0</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">。</font><font SIZE="3"> 
</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">（</font><font SIZE="3">2</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">）除数太小，被除数太大，导致商溢出。</p>
</font><font SIZE="3">
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">3.10 
</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">（</font><font SIZE="3">1</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">）</font><font SIZE="3">cbw 
</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">（</font><font SIZE="3">2</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">）</font><font SIZE="3">cwd 
</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">（</font><font SIZE="3">3</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">）</font><font SIZE="3">cdq 
</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">（</font><font SIZE="3">4</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">）</font><font SIZE="3">bt 
ax, 0</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">3.11 
</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">（</font><font SIZE="3">1</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">）</font><font SIZE="3"> 
mov ah, 0<br>
&nbsp; <br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
add ax, bx</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20"></font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">&nbsp;&nbsp;&nbsp;&nbsp; 
（</font><font SIZE="3">2</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">）</font><font SIZE="3"> 
cbw</font></p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20"><font size="3">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
add ax, bx</font></p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20"><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">&nbsp;&nbsp;&nbsp;&nbsp; 
（</font><font SIZE="3">3</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">）</font><font SIZE="3"> 
movsx eax, al</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
add eax, ebx</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">3.12 
</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">将</font><font SIZE="3">DX:AX</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">中的双字数右移</font><font SIZE="3">4</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">位。</p>
</font><font SIZE="3">
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">3.13 
</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">指令</font><font SIZE="3"> 
AL CF OF SF ZF</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">xor&nbsp;&nbsp;&nbsp; 
al, al&nbsp;&nbsp;&nbsp; 0&nbsp;&nbsp;&nbsp;&nbsp; 0&nbsp;&nbsp; 
0&nbsp;&nbsp;&nbsp; 0&nbsp;&nbsp; 1</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">mov&nbsp;&nbsp;&nbsp; 
al, 255&nbsp;&nbsp; 0ffh&nbsp; 0&nbsp;&nbsp; 0&nbsp;&nbsp;&nbsp; 0&nbsp;&nbsp; 1</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">inc&nbsp;&nbsp;&nbsp; 
al&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0&nbsp;&nbsp;&nbsp; 
0&nbsp;&nbsp; 0&nbsp;&nbsp;&nbsp; 0&nbsp;&nbsp; 1</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">not&nbsp;&nbsp;&nbsp; 
al&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0ffh&nbsp;&nbsp; 0&nbsp;&nbsp; 
0&nbsp;&nbsp;&nbsp; 0&nbsp;&nbsp; 1</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">shl&nbsp;&nbsp;&nbsp; 
al, 1&nbsp;&nbsp;&nbsp; 0feh&nbsp;&nbsp; 1&nbsp;&nbsp; 0&nbsp;&nbsp;&nbsp; 
1&nbsp;&nbsp; 0</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">cmp&nbsp;&nbsp;&nbsp; 
al, 10&nbsp;&nbsp; 0feh&nbsp;&nbsp; 0&nbsp;&nbsp; 0&nbsp;&nbsp;&nbsp; 
1&nbsp;&nbsp; 0</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">sub&nbsp;&nbsp;&nbsp; 
al, 7fh&nbsp; 7fh&nbsp;&nbsp;&nbsp; 0&nbsp;&nbsp; 1&nbsp;&nbsp;&nbsp; 
0&nbsp;&nbsp; 0</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">shl&nbsp;&nbsp;&nbsp; 
al, 1&nbsp;&nbsp;&nbsp; 0feh&nbsp;&nbsp; 0&nbsp;&nbsp; 1&nbsp;&nbsp;&nbsp; 
1&nbsp;&nbsp; 0</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">3.14</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20"><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">&nbsp;（</font><font SIZE="3">1</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">）</font><font SIZE="3">&nbsp;&nbsp; 
jcxz&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; done<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </font>next:&nbsp;&nbsp; mov&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
bl, [si]</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
mov&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; es:[di], bl</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
inc&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; si</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
inc&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; di</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
loop&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; next</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">done:</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20"></font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">（</font><font SIZE="3">2</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">）</font><font SIZE="3"> 
&nbsp;&nbsp; jcxz&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; done</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">next:&nbsp;&nbsp;&nbsp; 
mov&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; es:[di], eax</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
sub&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; di, 4</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
loop&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; next</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">done:</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20"></font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">（</font><font SIZE="3">3</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">）</font><font SIZE="3"> 
&nbsp; jcxz&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; done</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">next:&nbsp;&nbsp; 
mov&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ax, [si]</p>
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    <p ALIGN="JUSTIFY">&nbsp;&nbsp;&nbsp;&nbsp; cmp&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    ax, es:[di]</p>
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<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
pushf</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
add&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; si, 2</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
add&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; di, 2</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
popf</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
loope&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; next</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">done:</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">3.15&nbsp; 
</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">将</font><font SIZE="3">AX</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">与</font><font SIZE="3">DX</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">中的</font><font SIZE="3">4</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">位十进制数对应的压缩</font><font SIZE="3">BCD</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">码相加，结果存入</font><font SIZE="3">AX</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">。</p>
</font><font SIZE="3">
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20"></font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">&nbsp;&nbsp;&nbsp; 
例如，若</font><font SIZE="3">AX = 1234H</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">，</font><font SIZE="3">DX 
= 5678H</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">，则结果</font><font SIZE="3">AX 
= 6912H</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">。</font><font SIZE="3"></p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">3.16</p>
</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">（</font><font SIZE="3">1</font><font FACE="??ì?,SimSun" LANG="ZH-CN" SIZE="3">）</font><font SIZE="3"> 
mov&nbsp;&nbsp;&nbsp;&nbsp; bl, al</p>
<p ALIGN="JUSTIFY" style="text-indent: 40; margin-left: 20; margin-right: 20">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;