49 lines
1.9 KiB
HTML
49 lines
1.9 KiB
HTML
<html><!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
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<html>
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<head>
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<title>80386 Programmer's Reference Manual -- Opcode AAD</title>
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</head>
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<body>
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<b>up:</b> <a href="C17.HTM" tppabs="http://webster.cs.ucr.edu/Page_TechDocs/Doc386/C17.HTM">Chapter 17 -- 80386 Instruction Set</a><br>
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<b>prev:</b><a href="AAA.HTM" tppabs="http://webster.cs.ucr.edu/Page_TechDocs/Doc386/AAA.HTM"> AAA ASCII Adjust after Addition</a><br>
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<b>next:</b><a href="AAM.HTM" tppabs="http://webster.cs.ucr.edu/Page_TechDocs/Doc386/AAM.HTM"> AAM ASCII Adjust AX after Multiply</a>
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<p>
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<hr>
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<p>
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<h1>AAD -- ASCII Adjust AX before Division</h1>
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<pre>
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Opcode Instruction Clocks Description
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D5 0A AAD 19 ASCII adjust AX before division
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</pre>
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<h2>Operation</h2>
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<pre>
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AL := AH * 10 + AL;
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AH := 0;
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</pre>
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<h2>Description</h2>
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AAD is used to prepare two unpacked BCD digits (the least-significant digit in AL, the most-significant digit in AH) for a division operation that will yield an unpacked result. This is accomplished by setting AL to AL + (10 * AH), and then setting AH to 0. AX is then equal to the binary equivalent of the original unpacked two-digit number.
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<h2>Flags Affected</h2>
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SF, ZF, and PF as described in <a href="APPC.HTM" tppabs="http://webster.cs.ucr.edu/Page_TechDocs/Doc386/APPC.HTM">Appendix C</a>; OF, AF, and CF are undefined
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<h2>Protected Mode Exceptions</h2>
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None
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<h2>Real Address Mode Exceptions</h2>
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None
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<h2>Virtual 8086 Mode Exceptions</h2>
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None
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<p>
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<hr>
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<p><b>up:</b> <a href="C17.HTM" tppabs="http://webster.cs.ucr.edu/Page_TechDocs/Doc386/C17.HTM">Chapter 17 -- 80386 Instruction Set</a><br>
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<b>prev:</b><a href="AAA.HTM" tppabs="http://webster.cs.ucr.edu/Page_TechDocs/Doc386/AAA.HTM"> AAA ASCII Adjust after Addition</a><br>
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<b>next:</b><a href="AAM.HTM" tppabs="http://webster.cs.ucr.edu/Page_TechDocs/Doc386/AAM.HTM"> AAM ASCII Adjust AX after Multiply</a>
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</body>
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