i386/i386.reference/appc.htm

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   4 <TITLE>80386 Programmer's Reference Manual -- Appendix C</TITLE>
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   8 Appendices</A><BR>
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  10 <A HREF="appb.htm">Appendix B -- Complete Flag Cross-Reference</A><BR>
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  12 <A HREF="appd.htm">Appendix D -- Condition Codes</A>
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  15 <P>
  16 <H1>Appendix C -- Status Flag Summary</H1>
  17
  18 <H3>Status Flags' Functions</H3>
  19
  20 <PRE>
  21 Bit  Name   Function
  22
  23  0   CF     Carry Flag -- Set on high-order bit carry or borrow; cleared
  24             otherwise.
  25  2   PF     Parity Flag -- Set if low-order eight bits of result contain
  26             an even number of 1 bits; cleared otherwise.
  27  4   AF     Adjust flag -- Set on carry from or borrow to the low order
  28             four bits of   AL; cleared otherwise. Used for decimal
  29             arithmetic.
  30  6   ZF     Zero Flag -- Set if result is zero; cleared otherwise.
  31  7   SF     Sign Flag -- Set equal to high-order bit of result (0 is
  32             positive, 1 if negative).
  33 11   OF     Overflow Flag -- Set if result is too large a positive number
  34             or too small a negative number (excluding sign-bit) to fit in
  35             destination operand; cleared otherwise.
  36 </PRE>
  37
  38 <H3>Key to Codes</H3>
  39
  40 <PRE>
  41 T     = instruction tests flag
  42 M     = instruction modifies flag
  43         (either sets or resets depending on operands)
  44 0     = instruction resets flag
  45 --    = instruction's effect on flag is undefined
  46 blank = instruction does not affect flag
  47 </PRE>
  48
  49 <PRE>
  50 Instruction            OF   SF   ZF   AF   PF   CF
  51 AAA                    --   --   --   TM   --   M
  52 AAS                    --   --   --   TM   --   M
  53 AAD                    --   M    M    --   M    --
  54 AAM                    --   M    M    --   M    --
  55 DAA                    --   M    M    TM   M    TM
  56 DAS                    --   M    M    TM   M    TM
  57 ADC                    M    M    M    M    M    TM
  58 ADD                    M    M    M    M    M    M
  59 SBB                    M    M    M    M    M    TM
  60 SUB                    M    M    M    M    M    M
  61 CMP                    M    M    M    M    M    M
  62 CMPS                   M    M    M    M    M    M
  63 SCAS                   M    M    M    M    M    M
  64 NEG                    M    M    M    M    M    M
  65 DEC                    M    M    M    M    M
  66 INC                    M    M    M    M    M
  67 IMUL                   M    --   --   --   --   M
  68 MUL                    M    --   --   --   --   M
  69 RCL/RCR 1              M                        TM
  70 RCL/RCR count          --                       TM
  71 ROL/ROR 1              M                        M
  72 ROL/ROR count          --                       M
  73 SAL/SAR/SHL/SHR 1      M    M    M    --   M    M
  74 SAL/SAR/SHL/SHR count  --   M    M    --   M    M
  75 SHLD/SHRD              --   M    M    --   M    M
  76 BSF/BSR                --   --   M    --   --   --
  77 BT/BTS/BTR/BTC         --   --   --   --   --   M
  78 AND                    0    M    M    --   M    0
  79 OR                     0    M    M    --   M    0
  80 TEST                   0    M    M    --   M    0
  81 XOR                    0    M    M    --   M    0
  82 </PRE>
  83 <P>
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  87 Appendices</A><BR>
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  89 <A HREF="appb.htm">Appendix B -- Complete Flag Cross-Reference</A><BR>
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  91 <A HREF="appd.htm">Appendix D -- Condition Codes</A>
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