hw/i386.reference/CLD.htm

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   4 <TITLE>80386 Programmer's Reference Manual -- Opcode CLD</TITLE>
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   8 Chapter 17 -- 80386 Instruction Set</A><BR>
   9 <B>prev:</B><A HREF="CLC.htm"> CLC Clear Carry Flag</A><BR>
  10 <B>next:</B><A HREF="CLI.htm"> CLI Clear Interrupt Flag</A>
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  13 <P>
  14 <H1>CLD -- Clear Direction Flag</H1>
  15
  16 <PRE>
  17 Opcode    Instruction     Clocks   Description
  18
  19 FC        CLD             2        Clear direction flag; SI and DI
  20                                    will increment during string
  21                                    instructions
  22 </PRE>
  23
  24 <H2>Operation</H2>
  25
  26 <PRE>
  27 DF := 0;
  28 </PRE>
  29
  30 <H2>Description</H2>
  31
  32 CLD clears the direction flag. No other flags or registers are affected.
  33 After CLD is executed, string operations will increment the index registers
  34 (SI and/or DI) that they use.
  35
  36 <H2>Flags Affected</H2>
  37
  38 DF := 0
  39
  40 <H2>Protected Mode Exceptions</H2>
  41
  42 None
  43
  44 <H2>Real Address Mode Exceptions</H2>
  45
  46 None
  47
  48 <H2>Virtual 8086 Mode Exceptions</H2>
  49
  50 None
  51
  52
  53 <P>
  54 <HR>
  55 <P>
  56 <B>up:</B> <A HREF="c17.htm">
  57 Chapter 17 -- 80386 Instruction Set</A><BR>
  58 <B>prev:</B><A HREF="CLC.htm"> CLC Clear Carry Flag</A><BR>
  59 <B>next:</B><A HREF="CLI.htm"> CLI Clear Interrupt Flag</A>
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