hw/i386.reference/AAD.htm

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   4 <TITLE>80386 Programmer's Reference Manual -- Opcode AAD</TITLE>
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   7 <B>up:</B> <A HREF="c17.htm">
   8 Chapter 17 -- 80386 Instruction Set</A><BR>
   9 <B>prev:</B><A HREF="AAA.htm"> AAA ASCII Adjust after Addition</A><BR>
  10 <B>next:</B><A HREF="AAM.htm"> AAM ASCII Adjust AX after Multiply</A>
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  14 <H1>AAD -- ASCII Adjust AX before Division</H1>
  15
  16 <PRE>
  17 Opcode    Instruction    Clocks    Description
  18
  19 D5 0A     AAD            19        ASCII adjust AX before division
  20 </PRE>
  21
  22 <H2>Operation</H2>
  23
  24 <PRE>
  25 AL := AH * 10 + AL;
  26 AH := 0;
  27 </PRE>
  28
  29 <H2>Description</H2>
  30
  31 AAD is used to prepare two unpacked BCD digits (the least-significant
  32 digit in AL, the most-significant digit in AH) for a division operation that
  33 will yield an unpacked result. This is accomplished by setting AL to
  34 AL + (10 * AH), and then setting AH to 0. AX is then equal to the binary
  35 equivalent of the original unpacked two-digit number.
  36
  37 <H2>Flags Affected</H2>
  38
  39 SF, ZF, and PF as described in <A HREF="appc.htm">Appendix C</A>; OF, AF, and CF are undefined
  40
  41 <H2>Protected Mode Exceptions</H2>
  42
  43 None
  44
  45 <H2>Real Address Mode Exceptions</H2>
  46
  47 None
  48
  49 <H2>Virtual 8086 Mode Exceptions</H2>
  50
  51 None
  52
  53
  54 <P>
  55 <HR>
  56 <P>
  57 <B>up:</B> <A HREF="c17.htm">
  58 Chapter 17 -- 80386 Instruction Set</A><BR>
  59 <B>prev:</B><A HREF="AAA.htm"> AAA ASCII Adjust after Addition</A><BR>
  60 <B>next:</B><A HREF="AAM.htm"> AAM ASCII Adjust AX after Multiply</A>
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