INTEL 汇编指令集

左手的ㄟ右手 2022-06-11 00:39 403阅读 0赞

转自 [http://www.moon-soft.com/doc/30105.htm\#770][http_www.moon-soft.com_doc_30105.htm_770]

## **CONTENT** ##

Intel 8086 Family Architecture
    
    Instruction Clock Cycle Calculation
    8088/8086  Effective Address (EA) Calculation
    Task State Calculation
    FLAGS - Intel 8086 Family Flags Register
    MSW - Machine Status Word (286+ only)
    8086/80186/80286/80386/80486 Instruction Set
         AAA - Ascii Adjust for Addition
         AAD - Ascii Adjust for Division
         AAM - Ascii Adjust for Multiplication
         AAS - Ascii Adjust for Subtraction
         ADC - Add With Carry
         ADD - Arithmetic Addition
         AND - Logical And
         ARPL - Adjusted Requested Privilege Level of Selector (286+ PM)
         BOUND - Array Index Bound Check (80188+)
         BSF - Bit Scan Forward (386+)
         BSR - Bit Scan Reverse  (386+)
         BSWAP - Byte Swap       (486+)
         BT - Bit Test           (386+)
         BTC - Bit Test with Compliment (386+)
         BTR - Bit Test with Reset (386+)
         BTS - Bit Test and Set  (386+)
         CALL - Procedure Call
         CBW - Convert Byte to Word
         CDQ - Convert Double to Quad (386+)
         CLC - Clear Carry
         CLD - Clear Direction Flag
         CLI - Clear Interrupt Flag (disable)
         CLTS - Clear Task Switched Flag (286+ privileged)
         CMC - Complement Carry Flag
         CMP - Compare
         CMPS - Compare String (Byte, Word or Doubleword)
         CMPXCHG - Compare and Exchange
         CWD - Convert Word to Doubleword
         CWDE - Convert Word to Extended Doubleword (386+)
         DAA - Decimal Adjust for Addition
         DAS - Decimal Adjust for Subtraction
         DEC - Decrement
         DIV - Divide
         ENTER - Make Stack Frame (80188+)
         ESC - Escape
         HLT - Halt CPU
         IDIV - Signed Integer Division
         IMUL - Signed Multiply
         IN - Input Byte or Word From Port
         INC - Increment
         INS - Input String from Port (80188+)
         INT - Interrupt
         INTO - Interrupt on Overflow
         INVD - Invalidate Cache  (486+)
         INVLPG - Invalidate Translation Look-Aside Buffer Entry (486+)
         IRET/IRETD - Interrupt Return
         Jxx - Jump Instructions Table
         JCXZ/JECXZ - Jump if Register (E)CX is Zero
         JMP - Unconditional Jump
         LAHF - Load Register AH From Flags
         LAR - Load Access Rights (286+ protected)
         LDS - Load Pointer Using DS
         LEA - Load Effective Address
         LEAVE - Restore Stack for Procedure Exit (80188+)
         LES - Load Pointer Using ES
         LFS - Load Pointer Using FS (386+)
         LGDT - Load Global Descriptor Table (286+ privileged)
         LIDT - Load Interrupt Descriptor Table (286+ privileged)
         LGS - Load Pointer Using GS (386+)
         LLDT - Load Local Descriptor Table (286+ privileged)
         LMSW - Load Machine Status Word (286+ privileged)
         LOCK - Lock Bus
         LODS - Load String (Byte, Word or Double)
         LOOP - Decrement CX and Loop if CX Not Zero
         LOOPE/LOOPZ - Loop While Equal / Loop While Zero
         LOOPNZ/LOOPNE - Loop While Not Zero / Loop While Not Equal
         LSL - Load Segment Limit (286+ protected)
         LSS - Load Pointer Using SS (386+)
         LTR - Load Task Register (286+ privileged)
         MOV - Move Byte or Word
         MOVS - Move String (Byte or Word)
         MOVSX - Move with Sign Extend (386+)
         MOVZX - Move with Zero Extend (386+)
         MUL - Unsigned Multiply
         NEG - Two's Complement Negation
         NOP - No Operation (90h)
         NOT - One's Compliment Negation (Logical NOT)
         OR - Inclusive Logical OR
         OUT - Output Data to Port
         OUTS - Output String to Port (80188+)
         POP - Pop Word off Stack
         POPA/POPAD - Pop All Registers onto Stack (80188+)
         POPF/POPFD - Pop Flags off Stack
         PUSH - Push Word onto Stack
         PUSHA/PUSHAD - Push All Registers onto Stack (80188+)
         PUSHF/PUSHFD - Push Flags onto Stack
         RCL - Rotate Through Carry Left
         RCR - Rotate Through Carry Right
         REP - Repeat String Operation
         REPE/REPZ - Repeat Equal / Repeat Zero
         REPNE/REPNZ - Repeat Not Equal / Repeat Not Zero
         RET/RETF - Return From Procedure
         ROL - Rotate Left
         ROR - Rotate Right
         SAHF - Store AH Register into FLAGS
         SAL/SHL - Shift Arithmetic Left / Shift Logical Left
         SAR - Shift Arithmetic Right
         SBB - Subtract with Borrow/Carry
         SCAS - Scan String  (Byte, Word or Doubleword)
         SETAE/SETNB - Set if Above or Equal / Set if Not Below (386+)
         SETB/SETNAE - Set if Below / Set if Not Above or Equal (386+)
         SETBE/SETNA - Set if Below or Equal / Set if Not Above (386+)
         SETE/SETZ - Set if Equal / Set if Zero (386+)
         SETNE/SETNZ - Set if Not Equal / Set if Not Zero (386+)
         SETL/SETNGE - Set if Less / Set if Not Greater or Equal (386+)
         SETGE/SETNL - Set if Greater or Equal / Set if Not Less (386+)
         SETLE/SETNG - Set if Less or Equal / Set if Not greater or Equal (386+)
         SETG/SETNLE - Set if Greater / Set if Not Less or Equal (386+)
         SETS - Set if Signed (386+)
         SETNS - Set if Not Signed (386+)
         SETC - Set if Carry (386+)
         SETNC - Set if Not Carry (386+)
         SETO - Set if Overflow (386+)
         SETNO - Set if Not Overflow (386+)
         SETP/SETPE - Set if Parity / Set if Parity Even  (386+)
         SETNP/SETPO - Set if No Parity / Set if Parity Odd (386+)
         SGDT - Store Global Descriptor Table (286+ privileged)
         SIDT - Store Interrupt Descriptor Table (286+ privileged)
         SHL - Shift Logical Left
         SHR - Shift Logical Right
         SHLD/SHRD - Double Precision Shift (386+)
         SLDT - Store Local Descriptor Table (286+ privileged)
         SMSW - Store Machine Status Word (286+ privileged)
         STC - Set Carry
         STD - Set Direction Flag
         STI - Set Interrupt Flag  (Enable Interrupts)
         STOS - Store String  (Byte, Word or Doubleword)
         STR - Store Task Register (286+ privileged)
         SUB - Subtract
         TEST - Test For Bit Pattern
         VERR - Verify Read (286+ protected)
         VERW - Verify Write (286+ protected)
         WAIT/FWAIT - Event Wait
         WBINVD - Write-Back and Invalidate Cache (486+)
         XCHG - Exchange
         XLAT/XLATB - Translate
         XOR - Exclusive OR

## TEXT ##

Intel 8086 Family Architecture
            General Purpose Registers               Segment Registers
            AH/AL  AX  (EAX)  Accumulator            CS     Code Segment
            BH/BL  BX  (EBX)  Base                   DS     Data Segment
            CH/CL  CX  (ECX)  Counter                SS     Stack Segment
            DH/DL  DX  (EDX)  Data                   ES     Extra Segment
                                                    (FS)    386 and newer
            (Exx) indicates 386+ 32 bit register    (GS)    386 and newer
    
            Pointer Registers                       Stack Registers
            SI (ESI)  Source Index                  SP (ESP)  Stack Pointer
            DI (EDI)  Destination Index             BP (EBP)  Base Pointer
            IP        Instruction Pointer
    
            Status Registers
            FLAGS Status Flags   (see FLAGS)
            Special Registers (386+ only)
            CR0     Control Register 0        DR0    Debug Register 0
            CR2     Control Register 2        DR1    Debug Register 1
            CR3     Control Register 3        DR2    Debug Register 2
                                              DR3    Debug Register 3
            TR4     Test Register 4           DR6    Debug Register 6
            TR5     Test Register 5           DR7    Debug Register 7
            TR6     Test Register 6
            TR7     Test Register 7
            
            Register          Default Segment    Valid Overrides
            BP                      SS              DS, ES, CS
            SI or DI                DS              ES, SS, CS
            DI strings              ES              None
            SI strings              DS              ES, SS, CS
            - see  CPU   DETECTING  Instruction Timing
    
    Instruction Clock Cycle Calculation
            Some instructions require additional clock cycles due to a "Next
            Instruction Component" identified by a "+m" in the instruction
            clock cycle listings.  This is due to the prefetch queue being
            purge on a control transfers.   Below is the general rule for
            calculating "m":
    
            88/86 not applicable
            286  "m" is the number of bytes in the next instruction
            386  "m" is the number of components in the next instruction
                    (the instruction coding (each byte), plus the data and
                    the displacement are all considered components)
    
    8088/8086 Effective Address (EA) Calculation
                       Description                            Clock Cycles
            Displacement                                            6
            Base or Index (BX,BP,SI,DI)                             5
            Displacement+(Base or Index)                            9
            Base+Index (BP+DI,BX+SI)                                7
            Base+Index (BP+SI,BX+DI)                                8
            Base+Index+Displacement (BP+DI,BX+SI)                  11
            Base+Index+Displacement (BP+SI+disp,BX+DI+disp)        12
    
            - add 4 cycles for word operands at odd addresses
            - add 2 cycles for segment override
            - 80188/80186 timings differ from those of the 8088/8086/80286
    
    Task State Calculation
            "TS" is defined as switching from VM/486 or 80286 TSS to one of
            the following:
                            +---------------------------------------+
                            |               New Task                |
                            +-------+-------+-------+-------+-------+
            +---------------+486 TSS|486 TSS|386 TSS|386 TSS|286 TSS|
            |   Old Task    | (VM=0)| (VM=1)| (VM=0)| (VM=1)|       |
            +---------------+-------+-------+-------+-------+-------+
            386 TSS (VM=0)  |       |       |  309  |  226  |  282  |
                            +-------+-------+-------+-------+-------+
            386 TSS (VM=1)  |       |       |  314  |  231  |  287  |
                            +-------+-------+-------+-------+-------+
            386 CPU/286 TSS |       |       |  307  |  224  |  280  |
                            +-------+-------+-------+-------+-------+
            486 CPU/286 TSS |  199  |  177  |       |       |  180  |
                            +---------------------------------------+
                                 
            Miscellaneous
            - all timings are for best case and do not take into account wait
              states, instruction alignment, the state of the prefetch queue,
              DMA refresh cycles, cache hits/misses or exception processing.
            - to convert clocks to nanoseconds divide one microsecond by the
              processor speed in MegaHertz:
       
              (1000MHz/(n MHz)) = X nanoseconds
            - see   8086 Architecture
    
    FLAGS - Intel 8086 Family Flags Register
          |11|10|F|E|D|C|B|A|9|8|7|6|5|4|3|2|1|0|
            |  | | | | | | | | | | | | | | | | +---  CF Carry Flag
            |  | | | | | | | | | | | | | | | +---  1
            |  | | | | | | | | | | | | | | +---  PF Parity Flag
            |  | | | | | | | | | | | | | +---  0
            |  | | | | | | | | | | | | +---  AF Auxiliary Flag
            |  | | | | | | | | | | | +---  0
            |  | | | | | | | | | | +---  ZF Zero Flag
            |  | | | | | | | | | +---  SF Sign Flag
            |  | | | | | | | | +---  TF Trap Flag  (Single Step)
            |  | | | | | | | +---  IF Interrupt Flag
            |  | | | | | | +---  DF Direction Flag
            |  | | | | | +---  OF Overflow flag
            |  | | | +-----  IOPL I/O Privilege Level  (286+ only)
            |  | | +-----  NT Nested Task Flag  (286+ only)
            |  | +-----  0
            |  +-----  RF Resume Flag (386+ only)
            +------  VM  Virtual Mode Flag (386+ only)
            - see   PUSHF  POPF  STI  CLI  STD  CLD
    
    MSW - Machine Status Word (286+ only)
          |31|30-5|4|3|2|1|0|  Machine Status Word
            |   |  | | | | +---- Protection Enable (PE)
            |   |  | | | +----- Math Present (MP)
            |   |  | | +------ Emulation (EM)
            |   |  | +------- Task Switched (TS)
            |   |  +-------- Extension Type (ET)
            |   +---------- Reserved
            +------------- Paging (PG)
    
            Bit 0   PE      Protection Enable, switches processor between
                            protected and real mode
            Bit 1   MP      Math Present, controls function of the WAIT
                            instruction
            Bit 2   EM      Emulation, indicates whether coprocessor functions
                            are to be emulated
            Bit 3   TS      Task Switched, set and interrogated by coprocessor
                            on task switches and when interpretting coprocessor
                            instructions
            Bit 4   ET      Extension Type, indicates type of coprocessor in
                            system
            Bits 5-30       Reserved
            bit 31  PG      Paging, indicates whether the processor uses page
                            tables to translate linear addresses to physical
                            addresses
            - see   SMSW  LMSW
    
    8086/80186/80286/80386/80486 Instruction Set
    AAA - Ascii Adjust for Addition
            Usage:  AAA
            Modifies flags: AF CF (OF,PF,SF,ZF undefined)
            Changes contents of AL to valid unpacked decimal.  The high order
            nibble is zeroed.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              8     3     4     3             1
    
    AAD - Ascii Adjust for Division
            Usage:  AAD
            Modifies flags: SF ZF PF (AF,CF,OF undefined)
            Used before dividing unpacked decimal numbers.   Multiplies AH by
            10 and the adds result into AL.  Sets AH to zero.  This instruction
            is also known to have an undocumented behavior.
            AL := 10*AH+AL
            AH := 0
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              60    14    19    14            2
    
    AAM - Ascii Adjust for Multiplication
            Usage:  AAM
            Modifies flags: PF SF ZF (AF,CF,OF undefined)
            AH := AL / 10
            AL := AL mod 10
            Used after multiplication of two unpacked decimal numbers, this
            instruction adjusts an unpacked decimal number.  The high order
            nibble of each byte must be zeroed before using this instruction.
            This instruction is also known to have an undocumented behavior.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              83    16    17    15            2
    
    AAS - Ascii Adjust for Subtraction
            Usage:  AAS
            Modifies flags: AF CF (OF,PF,SF,ZF undefined)
            Corrects result of a previous unpacked decimal subtraction in AL.
            High order nibble is zeroed.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              8     3     4     3             1
            
            
    ADC - Add With Carry
            Usage:  ADC     dest,src
            Modifies flags: AF CF OF SF PF ZF
            Sums two binary operands placing the result in the destination.
            If CF is set, a 1 is added to the destination.
                                    Clocks                  Size
            Operands         808x  286   386   486          Bytes
            reg,reg           3     2     2     1             2
            mem,reg         16+EA   7     7     3            2-4  (W88=24+EA)
            reg,mem          9+EA   7     6     2            2-4  (W88=13+EA)
            reg,immed         4     3     2     1            3-4
            mem,immed       17+EA   7     7     3            3-6  (W88=23+EA)
            accum,immed       4     3     2     1            2-3
    
    ADD - Arithmetic Addition
            Usage:  ADD     dest,src
            Modifies flags: AF CF OF PF SF ZF
            Adds "src" to "dest" and replacing the original contents of "dest".
            Both operands are binary.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,reg           3     2     2     1             2
            mem,reg         16+EA   7     7     3            2-4  (W88=24+EA)
            reg,mem          9+EA   7     6     2            2-4  (W88=13+EA)
            reg,immed         4     3     2     1            3-4
            mem,immed       17+EA   7     7     3            3-6  (W88=23+EA)
            accum,immed       4     3     2     1            2-3
    
    AND - Logical And
            Usage:  AND     dest,src
            Modifies flags: CF OF PF SF ZF (AF undefined)
            Performs a logical AND of the two operands replacing the destination
            with the result.
                                    Clocks                  Size
            Operands         808x  286   386   486          Bytes
            reg,reg           3     2     2     1             2
            mem,reg         16+EA   7     7     3            2-4  (W88=24+EA)
            reg,mem          9+EA   7     6     1            2-4  (W88=13+EA)
            reg,immed         4     3     2     1            3-4
            mem,immed       17+EA   7     7     3            3-6  (W88=23+EA)
            accum,immed       4     3     2     1            2-3
    
    ARPL - Adjusted Requested Privilege Level of Selector (286+ PM)
            Usage:  ARPL    dest,src
            (286+ protected mode)
            Modifies flags: ZF
            Compares the RPL bits of "dest" against "src".  If the RPL bits
            of "dest" are less than "src", the destination RPL bits are set
            equal to the source RPL bits and the Zero Flag is set.  Otherwise
            the Zero Flag is cleared.
                                    Clocks                  Size
            Operands         808x  286   386   486          Bytes
            reg,reg           -     10    20    9             2
            mem,reg           -     11    21    9             4
            
    BOUND - Array Index Bound Check (80188+)
            Usage:  BOUND   src,limit
            Modifies flags: None
            Array index in source register is checked against upper and lower
            bounds in memory source.  The first word located at "limit" is
            the lower boundary and the word at "limit+2" is the upper array bound.
            Interrupt 5 occurs if the source value is less than or higher than
            the source.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16,mem32       -   nj=13 nj=10   7             2
            reg32,mem64       -   nj=13 nj=10   7             2
            - nj = no jump taken
    
    BSF - Bit Scan Forward (386+)
            Usage:  BSF     dest,src
            Modifies flags: ZF
            Scans source operand for first bit set.  Sets ZF if a bit is found
            set and loads the destination with an index to first set bit.  Clears
            ZF is no bits are found set.  BSF scans forward across bit pattern
            (0-n) while BSR scans in reverse (n-0).
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,reg           -     -   10+3n  6-42           3
            reg,mem           -     -   10+3n  7-43          3-7
            reg32,reg32       -     -   10+3n  6-42          3-7
            reg32,mem32       -     -   10+3n  7-43          3-7
    
    BSR - Bit Scan Reverse (386+)
            Usage:  BSR     dest,src
            Modifies flags: ZF
            Scans source operand for first bit set.  Sets ZF if a bit is found
            set and loads the destination with an index to first set bit.  Clears
            ZF is no bits are found set.  BSF scans forward across bit pattern
            (0-n) while BSR scans in reverse (n-0).
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,reg           -     -   10+3n  6-103          3
            reg,mem           -     -   10+3n  7-104         3-7
            reg32,reg32       -     -   10+3n  6-103         3-7
            reg32,mem32       -     -   10+3n  7-104         3-7
    
    BSWAP - Byte Swap (486+)
            Usage:  BSWAP   reg32
            Modifies flags: none
            Changes the byte order of a 32 bit register from big endian to
            little endian or vice versa.   Result left in destination register
            is undefined if the operand is a 16 bit register.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg32             -     -     -     1             2
    
    BT - Bit Test (386+)
            Usage:  BT      dest,src
            Modifies flags: CF
            The destination bit indexed by the source value is copied into the
            Carry Flag.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16,immed8      -     -     3     3            4-8
            mem16,immed8      -     -     6     6            4-8
            reg16,reg16       -     -     3     3            3-7
            mem16,reg16       -     -     12    12           3-7
    
    BTC - Bit Test with Compliment (386+)
            Usage:  BTC     dest,src
            Modifies flags: CF
            The destination bit indexed by the source value is copied into the
            Carry Flag after being complimented (inverted).
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16,immed8      -     -     6     6            4-8
            mem16,immed8      -     -     8     8            4-8
            reg16,reg16       -     -     6     6            3-7
            mem16,reg16       -     -     13    13           3-7
    
    BTR - Bit Test with Reset (386+)
            Usage:  BTR     dest,src
            Modifies flags: CF
            The destination bit indexed by the source value is copied into the
            Carry Flag and then cleared in the destination.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16,immed8      -     -     6     6            4-8
            mem16,immed8      -     -     8     8            4-8
            reg16,reg16       -     -     6     6            3-7
            mem16,reg16       -     -     13    13           3-7
    
    BTS - Bit Test and Set (386+)
            Usage:  BTS     dest,src
            Modifies flags: CF
            The destination bit indexed by the source value is copied into the
            Carry Flag and then set in the destination.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16,immed8      -     -     6     6            4-8
            mem16,immed8      -     -     8     8            4-8
            reg16,reg16       -     -     6     6            3-7
            mem16,reg16       -     -     13    13           3-7
    
    CALL - Procedure Call
            Usage:  CALL    destination
            Modifies flags: None
            Pushes Instruction Pointer (and Code Segment for far calls) onto
            stack and loads Instruction Pointer with the address of proc-name.
            Code continues with execution at CS:IP.
                                                             Clocks
                       Operands                     808x   286     386     486
            rel16 (near, IP relative)                19     7      7+m      3
            rel32 (near, IP relative)                -      -      7+m      3
            reg16 (near, register indirect)          16     7      7+m      5
            reg32 (near, register indirect)          -      -      7+m      5
            mem16 (near, memory indirect)          21+EA    11    10+m      5
            mem32 (near, memory indirect)            -      -     10+m      5
            ptr16:16 (far, full ptr supplied)        28     13    17+m      18
            ptr16:32 (far, full ptr supplied)        -      -     17+m      18
            ptr16:16 (far, ptr supplied, prot. mode) -      26    34+m      20
            ptr16:32 (far, ptr supplied, prot. mode) -      -     34+m      20
            m16:16 (far, indirect)                 37+EA    16    22+m      17
            m16:32 (far, indirect)                   -      -     22+m      17
            m16:16 (far, indirect, prot. mode)       -      29    38+m      20
            m16:32 (far, indirect, prot. mode)       -      -     38+m      20
            ptr16:16 (task, via TSS or task gate)    -     177     TS     37+TS
            m16:16 (task, via TSS or task gate)      -   180/185  5+TS    37+TS
            m16:32 (task)                            -      -      TS     37+TS
            m16:32 (task)                            -      -     5+TS    37+TS
            ptr16:16 (gate, same privilege)          -      41    52+m      35
            ptr16:32 (gate, same privilege)          -      -     52+m      35
            m16:16 (gate, same privilege)            -      44    56+m      35
            m16:32 (gate, same privilege)            -      -     56+m      35
            ptr16:16 (gate, more priv, no parm)      -      82    86+m      69
            ptr16:32 (gate, more priv, no parm)      -      -     86+m      69
            m16:16 (gate, more priv, no parm)        -      83    90+m      69
            m16:32 (gate, more priv, no parm)        -      -     90+m      69
            ptr16:16 (gate, more priv, x parms)      -    86+4x  94+4x+m  77+4x
            ptr16:32 (gate, more priv, x parms)      -      -    94+4x+m  77+4x
            m16:16 (gate, more priv, x parms)        -    90+4x  98+4x+m  77+4x
            m16:32 (gate, more priv, x parms)        -      -    98+4x+m  77+4x
    
    CBW - Convert Byte to Word
            Usage:  CBW
            Modifies flags: None
            Converts byte in AL to word Value in AX by extending sign of AL
            throughout register AH.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              2     2     3     3             1
    
    CDQ - Convert Double to Quad (386+)
            Usage:  CDQ
            Modifies flags: None
            Converts signed DWORD in EAX to a signed quad word in EDX:EAX by
            extending the high order bit of EAX throughout EDX
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              -     -     2     3             1
    
    CLC - Clear Carry
            Usage:  CLC
            Modifies flags: CF
            Clears the Carry Flag.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              2     2     2     2             1
    
    CLD - Clear Direction Flag
            Usage:  CLD
            Modifies flags: DF
            Clears the Direction Flag causing string instructions to increment
            the SI and DI index registers.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              2     2     2     2             1
    
    CLI - Clear Interrupt Flag (disable)
            Usage:  CLI
            Modifies flags: IF
            Disables the maskable hardware interrupts by clearing the Interrupt
            flag.  NMI's and software interrupts are not inhibited.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              2     2     3     5             1
    
    CLTS - Clear Task Switched Flag (286+ privileged)
            Usage:  CLTS
            Modifies flags: None
            Clears the Task Switched Flag in the Machine Status Register.  This
            is a privileged operation and is generally used only by operating
            system code.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              -     2     5     7             2
    
    CMC - Complement Carry Flag
            Usage:  CMC
            Modifies flags: CF
            Toggles (inverts) the Carry Flag
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              2     2     2     2             1
    
    CMP - Compare
            Usage:  CMP     dest,src
            Modifies flags: AF CF OF PF SF ZF
            Subtracts source from destination and updates the flags but does
            not save result.  Flags can subsequently be checked for conditions.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,reg           3     2     2     1             2
            mem,reg          9+EA   7     5     2            2-4  (W88=13+EA)
            reg,mem          9+EA   6     6     2            2-4  (W88=13+EA)
            reg,immed         4     3     2     1            3-4
            mem,immed       10+EA   6     5     2            3-6  (W88=14+EA)
            accum,immed       4     3     2     1            2-3
    
    CMPS - Compare String (Byte, Word or Doubleword)
            Usage:  CMPS    dest,src
                    CMPSB
                    CMPSW
                    CMPSD   (386+)
            Modifies flags: AF CF OF PF SF ZF
            Subtracts destination value from source without saving results.
            Updates flags based on the subtraction and  the index registers
            (E)SI and (E)DI are incremented or decremented depending on the
            state of the Direction Flag.  CMPSB inc/decrements the index
            registers by 1, CMPSW inc/decrements by 2, while CMPSD increments
            or decrements by 4.  The REP prefixes can be used to process
            entire data items.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            dest,src          22    8     10    8             1  (W88=30)
    
    CMPXCHG - Compare and Exchange
            Usage:  CMPXCHG dest,src  (486+)
            Modifies flags: AF CF OF PF SF ZF
            Compares the accumulator (8-32 bits) with "dest".  If equal the
            "dest" is loaded with "src", otherwise the accumulator is loaded
            with "dest".
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,reg           -     -     -     6             2
            mem,reg           -     -     -     7             2
            - add 3 clocks if the "mem,reg" comparison fails
    
    CWD - Convert Word to Doubleword
            Usage:  CWD
            Modifies flags: None
            Extends sign of word in register AX throughout register DX forming
            a doubleword quantity in DX:AX.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              5     2     2     3             1
    
    CWDE - Convert Word to Extended Doubleword (386+)
            Usage:  CWDE
            Modifies flags: None
            Converts a signed word in AX to a signed doubleword in EAX by
            extending the sign bit of AX throughout EAX.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              -     -     3     3             1
    
    DAA - Decimal Adjust for Addition
            Usage:  DAA
            Modifies flags: AF CF PF SF ZF (OF undefined)
            Corrects result (in AL) of a previous BCD addition operation.
            Contents of AL are changed to a pair of packed decimal digits.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              4     3     4     2             1
    
    DAS - Decimal Adjust for Subtraction
            Usage:  DAS
            Modifies flags: AF CF PF SF ZF (OF undefined)
            Corrects result (in AL) of a previous BCD subtraction operation.
            Contents of AL are changed to a pair of packed decimal digits.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              4     3     4     2             1
    
    DEC - Decrement
            Usage:  DEC     dest
            Modifies flags: AF OF PF SF ZF
            Unsigned binary subtraction of one from the destination.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              3     2     2     1             2
            mem             15+EA   7     6     3            2-4
            reg16/32          3     2     2     1             1
    
    DIV - Divide
            Usage:  DIV     src
            Modifies flags: (AF,CF,OF,PF,SF,ZF undefined)
            Unsigned binary division of accumulator by source.  If the source
            divisor is a byte value then AX is divided by "src" and the quotient
            is placed in AL and the remainder in AH.  If source operand is a word
            value, then DX:AX is divided by "src" and the quotient is stored in AX
            and the remainder in DX.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8             80-90  14    14    16            2
            reg16           144-162 22    22    24            2
            reg32              -    -     38    40            2
            mem8        (86-96)+EA  17    17    16           2-4
            mem16     (150-168)+EA  25    25    24           2-4  (W88=158-176+EA)
            mem32              -    -     41    40           2-4
    
    ENTER - Make Stack Frame (80188+)
            Usage:  ENTER   locals,level
            Modifies flags: None
            Modifies stack for entry to procedure for high level language.
            Operand "locals" specifies the amount of storage to be allocated
            on the stack.   "Level" specifies the nesting level of the routine.
            Paired with the LEAVE instruction, this is an efficient method of
            entry and exit to procedures.
                                         Clocks                     Size
            Operands         808x    286       386       486        Bytes
            immed16,0         -       11       10         14          4
            immed16,1         -       15       12         17          4
            immed16,immed8    -   12+4(n-1) 15+4(n-1)    17+3n        4
    
    ESC - Escape
            Usage:  ESC     immed,src
            Modifies flags: None
            Provides access to the data bus for other resident processors.
            The CPU treats it as a NOP but places memory operand on bus.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            immed,reg         2   9-20    ?                   2
            immed,mem         2   9-20    ?                  2-4
    
    HLT - Halt CPU
            Usage:   HLT
            Modifies flags: None
            Halts CPU until RESET line is activated, NMI or maskable interrupt
            received.  The CPU becomes dormant but retains the current CS:IP
            for later restart.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              2     2     5     4             1
    
    IDIV - Signed Integer Division
            Usage:   IDIV   src
            Modifies flags: (AF,CF,OF,PF,SF,ZF undefined)
            Signed binary division of accumulator by source.  If source is a
            byte value, AX is divided by "src" and the quotient is stored in
            AL and the remainder in AH.  If source is a word value, DX:AX is
            divided by "src", and the quotient is stored in AL and the
            remainder in DX.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8          101-112   17    19    19            2
            reg16         165-184   25    27    27            2
            reg32            -      -     43    43            2
            mem8     (107-118)+EA   20    22    20           2-4
            mem16    (171-190)+EA   38    30    28           2-4  (W88=175-194)
            mem32            -      -     46    44           2-4
    
    IMUL - Signed Multiply
            Usage:  IMUL    src
                    IMUL    src,immed        (286+)
                    IMUL    dest,src,immed8  (286+)
                    IMUL    dest,src         (386+)
            Modifies flags: CF OF (AF,PF,SF,ZF undefined)
            Signed multiplication of accumulator by "src" with result placed
            in the accumulator.  If the source operand is a byte value, it
            is multiplied by AL and the result stored in AX.  If the source
            operand is a word value it is multiplied by AX and the result is
            stored in DX:AX.  Other variations of this instruction allow
            specification of source and destination registers as well as a
            third immediate factor.
                                      Clocks                Size
            Operands         808x   286   386   486         Bytes
            reg8             80-98   13   9-14  13-18         2
            reg16           128-154  21   9-22  13-26         2
            reg32              -     -    9-38  12-42         2
            mem8             86-104  16  12-17  13-18        2-4
            mem16           134-160  24  12-25  13-26        2-4
            mem32              -     -   12-41  13-42        2-4
            reg16,reg16        -     -    9-22  13-26        3-5
            reg32,reg32        -     -    9-38  13-42        3-5
            reg16,mem16        -     -   12-25  13-26        3-5
            reg32,mem32        -     -   12-41  13-42        3-5
            reg16,immed        -     21   9-22  13-26         3
            reg32,immed        -     21   9-38  13-42        3-6
            reg16,reg16,immed  -     2    9-22  13-26        3-6
            reg32,reg32,immed  -     21   9-38  13-42        3-6
            reg16,mem16,immed  -     24  12-25  13-26        3-6
            reg32,mem32,immed  -     24  12-41  13-42        3-6
    
    IN - Input Byte or Word From Port
            Usage:  IN      accum,port
            Modifies flags: None
            A byte, word or dword is read from "port" and placed in AL, AX or
            EAX respectively.  If the port number is in the range of 0-255
            it can be specified as an immediate, otherwise the port number
            must be specified in DX.  Valid port ranges on the PC are 0-1024,
            though values through 65535 may be specified and recognized by
            third party vendors and PS/2's.
                                     Clocks                 Size
            Operands         808x  286   386    486         Bytes
            accum,immed8    10/14   5     12     14           2
            accum,immed8 (PM)            6/26  8/28/27        2
            accum,DX         8/12   5     13     14           1
            accum,DX (PM)                7/27  8/28/27        1
            - 386+ protected mode timings depend on privilege levels.
              first number is the timing if:    CPL ?IOPL
              second number is the timing if:   CPL > IOPL or in VM 86 mode (386)
                                                CPL ?IOPL  (486)
              third number is the timing when:    virtual mode on 486 processor
            - 486 virtual mode always requires 27 cycles
    
    INC - Increment
            Usage:  INC     dest
            Modifies flags: AF OF PF SF ZF
            Adds one to destination unsigned binary operand.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              3     2     2     1             2
            reg16             3     2     2     1             1
            reg32             3     2     2     1             1
            mem             15+EA   7     6     3            2-4  (W88=23+EA)
    
    INS - Input String from Port (80188+)
            Usage:  INS     dest,port
                    INSB
                    INSW
                    INSD    (386+)
            Modifies flags: None
            Loads data from port to the destination ES:(E)DI  (even if a
            destination operand is supplied).  (E)DI is adjusted by the size
            of the operand and increased if the Direction Flag is cleared and
            decreased if the Direction Flag is set.  For INSB, INSW, INSD no
            operands are allowed and the size is determined by the mnemonic.
                                     Clocks                 Size
            Operands         808x  286   386    486         Bytes
            dest,port         -     5     15     17           1
            dest,port (PM)    -     5    9/29 10/32/30        1
            none              -     5     15     17           1
            none (PM)         -     5    9/29 10/32/30        1
            - 386+ protected mode timings depend on privilege levels.
              first number is the timing if:    CPL ?IOPL
              second number is the timing if:   CPL > IOPL
              third number is the timing if:    virtual mode on 486 processor
    
    INT - Interrupt
            Usage:  INT     num
            Modifies flags: TF IF
            Initiates a software interrupt by pushing the flags, clearing the
            Trap and Interrupt Flags, pushing CS followed by IP and loading
            CS:IP with the value found in the interrupt vector table.  Execution
            then begins at the location addressed by the new CS:IP
                                                   Clocks           Size
                Operands                    808x  286   386   486   Bytes
     3 (constant)                          52/72  23+m   33    26     2
     3 (prot. mode, same priv.)              -    40+m   59    44     2       
     3 (prot. mode, more priv.)              -    78+m   99    71     2
     3 (from VM86 to PL 0)                   -     -    119    82     2
     3 (prot. mode via task gate)            -   167+m   TS  37+TS    2
     immed8                                51/71  23+m   37    30     1
     immed8 (prot. mode, same priv.)         -    40+m   59    44     1
     immed8 (prot. mode, more priv.)         -    78+m   99    71     1
     immed8 (from VM86 to PL 0)              -     -    119    86     1
     immed8 (prot. mode, via task gate)      -   167+m   TS  37+TS    1
    
    INTO - Interrupt on Overflow
            Usage:  INTO
            Modifies flags: IF TF
            If the Overflow Flag is set this instruction generates an INT 4
            which causes the code addressed by 0000:0010 to be executed.
                                              Clocks           Size
            Operands                808x    286   386   486    Bytes
            none: jump             53/73   24+m    35    28      1
                  no jump            4       3     3     3
            (prot. mode, same priv.) -       -     59    46      1
            (prot. mode, more priv.) -       -     99    73      1
            (from VM86 to PL 0)      -       -    119    84      1
            (prot. mode, via task gate)      -     TS  39+TS     1
    
    INVD - Invalidate Cache (486+)
            Usage:  INVD
            Modifies flags: none
            Flushes CPU internal cache.  Issues special function bus cycle
            which indicates to flush external caches.   Data in write-back
            external caches is lost.
            
                                      Clocks                Size
            Operands         808x   286   386   486         Bytes
            none              -      -     -     4            2
    
    INVLPG - Invalidate Translation Look-Aside Buffer Entry (486+)
            Usage:  INVLPG
            Modifies flags: none
            Invalidates a single page table entry in the Translation
            Look-Aside Buffer.  Intel warns that this instruction may be
            implemented differently on future processors.
            
                                      Clocks                Size
            Operands         808x   286   386   486         Bytes
            none              -      -     -     12           2
            - timing is for TLB entry hit only.
    
    IRET/IRETD - Interrupt Return
            Usage:  IRET
                    IRETD  (386+)
            Modifies flags: AF CF DF IF PF SF TF ZF
            Returns control to point of interruption by popping IP, CS
            and then the Flags from the stack and continues execution at
            this location.  CPU exception interrupts will return to the
            instruction that cause the exception because the CS:IP placed
            on the stack during the interrupt is the address of the offending
            instruction.
                                             Clocks                 Size
                Operands            808x   286   386   486          Bytes
        iret                       32/44  17+m    22    15            1
        iret  (prot. mode)           -    31+m    38    15            1
        iret  (to less privilege)    -    55+m    82    36            1
        iret  (different task, NT=1) -   169+m    TS  TS+32           1
        iretd                        -      -   22/38   15            1
        iretd (to less privilege)    -      -     82    36            1
        iretd (to VM86 mode)         -      -     60    15            1
        iretd (different task, NT=1) -      -     TS  TS+32           1
        - 386 timings are listed as real-mode/protected-mode
    
    Jxx - Jump Instructions Table
            Mnemonic              Meaning                    Jump Condition
              JA     Jump if Above                         CF=0 and ZF=0
              JAE    Jump if Above or Equal                CF=0
              JB     Jump if Below                         CF=1
              JBE    Jump if Below or Equal                CF=1 or ZF=1
              JC     Jump if Carry                         CF=1
              JCXZ   Jump if CX Zero                       CX=0
              JE     Jump if Equal                         ZF=1
              JG     Jump if Greater (signed)              ZF=0 and SF=OF
              JGE    Jump if Greater or Equal (signed)     SF=OF
              JL     Jump if Less (signed)                 SF != OF
              JLE    Jump if Less or Equal (signed)        ZF=1 or SF != OF
              JMP    Unconditional Jump                    unconditional
              JNA    Jump if Not Above                     CF=1 or ZF=1
              JNAE   Jump if Not Above or Equal            CF=1
              JNB    Jump if Not Below                     CF=0
              JNBE   Jump if Not Below or Equal            CF=0 and ZF=0
              JNC    Jump if Not Carry                     CF=0
              JNE    Jump if Not Equal                     ZF=0
              JNG    Jump if Not Greater (signed)          ZF=1 or SF != OF
              JNGE   Jump if Not Greater or Equal (signed) SF != OF
              JNL    Jump if Not Less (signed)             SF=OF
              JNLE   Jump if Not Less or Equal (signed)    ZF=0 and SF=OF
              JNO    Jump if Not Overflow (signed)         OF=0
              JNP    Jump if No Parity                     PF=0
              JNS    Jump if Not Signed (signed)           SF=0
              JNZ    Jump if Not Zero                      ZF=0
              JO     Jump if Overflow (signed)             OF=1
              JP     Jump if Parity                        PF=1
              JPE    Jump if Parity Even                   PF=1
              JPO    Jump if Parity Odd                    PF=0
              JS     Jump if Signed (signed)               SF=1
              JZ     Jump if Zero                          ZF=1
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            Jx: jump          16   7+m   7+m    3             2
                no jump        4    3     3     1
            Jx  near-label     -    -    7+m    3             4
                no jump        -    -     3     1
            - It's a good programming practice to organize code so the
              expected case is executed without a jump since the actual
              jump takes longer to execute than falling through the test.
            - see   JCXZ  and  JMP  for their respective timings
    
    JCXZ/JECXZ - Jump if Register (E)CX is Zero
            Usage:  JCXZ    label
                    JECXZ   label  (386+)
            Modifies flags: None
            Causes execution to branch to "label" if register CX is zero.  Uses
            unsigned comparision.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            label:  jump      18   8+m   9+m    8             2
                    no jump    6    4     5     5
    
    JMP - Unconditional Jump
            Usage:  JMP     target
            Modifies flags: None
            Unconditionally transfers control to "label".  Jumps by default
            are within -32768 to 32767 bytes from the instruction following
            the jump.  NEAR and SHORT jumps cause the IP to be updated while FAR
            jumps cause CS and IP to be updated.
                                                            Clocks
                       Operands                     808x  286    386   486
            rel8  (relative)                        15    7+m    7+m    3
            rel16 (relative)                        15    7+m    7+m    3
            rel32 (relative)                         -     -     7+m    3
            reg16 (near, register indirect)         11    7+m    7+m    5
            reg32 (near, register indirect)          -     -     7+m    5
            mem16 (near, mem indirect)             18+EA  11+m  10+m    5
            mem32 (near, mem indirect)             24+EA  15+m  10+m    5
            ptr16:16 (far, dword immed)              -     -    12+m    17
            ptr16:16 (far, PM dword immed)           -     -    27+m    19
            ptr16:16 (call gate, same priv.)         -    38+m  45+m    32
            ptr16:16 (via TSS)                       -   175+m   TS   42+TS
            ptr16:16 (via task gate)                 -   180+m   TS   43+TS
            mem16:16 (far, indirect)                 -     -    43+m    13
            mem16:16 (far, PM indirect)              -     -    31+m    18
            mem16:16 (call gate, same priv.)         -    41+m  49+m    31
            mem16:16 (via TSS)                       -   178+m  5+TS  41+TS
            mem16:16 (via task gate)                 -   183+m  5+TS  42+TS
            ptr16:32 (far, 6 byte immed)             -     -    12+m    13
            ptr16:32 (far, PM 6 byte immed)          -     -    27+m    18
            ptr16:32 (call gate, same priv.)         -     -    45+m    31
            ptr16:32 (via TSS)                       -     -     TS   42+TS
            ptr16:32 (via task state)                -     -     TS   43+TS
            m16:32 (far, address at dword)           -     -    43+m    13
            m16:32 (far, address at dword)           -     -    31+m    18
            m16:32 (call gate, same priv.)           -     -    49+m    31
            m16:32 (via TSS)                         -     -    5+TS  41+TS
            m16:32 (via task state)                  -     -    5+TS  42+TS
    
    LAHF - Load Register AH From Flags
            Usage:  LAHF
            Modifies flags: None
            Copies bits 0-7 of the flags register into AH.  This includes flags
            AF, CF, PF, SF and ZF other bits are undefined.
            AH := SF ZF xx AF xx PF xx CF
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              4     2     2     3             1
    
    LAR - Load Access Rights (286+ protected)
            Usage:  LAR     dest,src
            Modifies flags: ZF
            The high byte of the of the destination register is overwritten by
            the value of the access rights byte and the low order byte is zeroed
            depending on the selection in the source operand.  The Zero Flag is
            set if the load operation is successful.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16,reg16       -     14    15    11            3
            reg32,reg32       -     -     15    11            3
            reg16,mem16       -     16    16    11           3-7
            reg32,mem32       -     -     16    11           3-7
    
    LDS - Load Pointer Using DS
            Usage:  LDS     dest,src
            Modifies flags: None
            Loads 32-bit pointer from memory source to destination register
            and DS.  The offset is placed in the destination register and the
            segment is placed in DS.  To use this instruction the word at the
            lower memory address must contain the offset and the word at the
            higher address must contain the segment.  This simplifies the loading
            of far pointers from the stack and the interrupt vector table.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16,mem32     16+EA   7     7     6            2-4
            reg,mem (PM)      -     -     22    12           5-7
    
    LEA - Load Effective Address
            Usage:  LEA     dest,src
            Modifies flags: None
            Transfers offset address of "src" to the destination register.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,mem          2+EA   3     2     1            2-4
            - the MOV instruction can often save clock cycles when used in
              place of LEA on 8088 processors
    
    LEAVE - Restore Stack for Procedure Exit (80188+)
            Usage:  LEAVE
            Modifies flags: None
            Releases the local variables created by the previous ENTER
            instruction by restoring SP and BP to their condition before
            the procedure stack frame was initialized.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              -     5     4     5             1
    
    LES - Load Pointer Using ES
            Usage:  LES     dest,src
            Modifies flags: None
            Loads 32-bit pointer from memory source to destination register
            and ES.  The offset is placed in the destination register and the
            segment is placed in ES.  To use this instruction the word at the
            lower memory address must contain the offset and the word at the
            higher address must contain the segment.  This simplifies the loading
            of far pointers from the stack and the interrupt vector table.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,mem         16+EA   7     7     6            2-4  (W88=24+EA)
            reg,mem (PM)      -     -     22    12           5-7
    
    LFS - Load Pointer Using FS (386+)
            Usage:  LFS     dest,src
            Modifies flags: None
            Loads 32-bit pointer from memory source to destination register
            and FS.  The offset is placed in the destination register and the
            segment is placed in FS.  To use this instruction the word at the
            lower memory address must contain the offset and the word at the
            higher address must contain the segment.  This simplifies the loading
            of far pointers from the stack and the interrupt vector table.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,mem           -     -     7     6            5-7
            reg,mem (PM)      -     -     22    12           5-7
    
    LGDT - Load Global Descriptor Table (286+ privileged)
            Usage:  LGDT    src
            Modifies flags: None
            Loads a value from an operand into the Global Descriptor Table
            (GDT) register.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            mem64             -     11    11    11            5
    
    LIDT - Load Interrupt Descriptor Table (286+ privileged)
            Usage:  LIDT    src
            Modifies flags: None
            Loads a value from an operand into the Interrupt Descriptor Table
            (IDT) register.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            mem64             -     12    11    11            5
    
    LGS - Load Pointer Using GS (386+)
            Usage:  LGS     dest,src
            Modifies flags: None
            Loads 32-bit pointer from memory source to destination register
            and GS.  The offset is placed in the destination register and the
            segment is placed in GS.  To use this instruction the word at the
            lower memory address must contain the offset and the word at the
            higher address must contain the segment.  This simplifies the loading
            of far pointers from the stack and the interrupt vector table.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,mem           -     -     7     6            5-7
            reg,mem (PM)      -     -     22    12           5-7
    
    LLDT - Load Local Descriptor Table (286+ privileged)
            Usage:  LLDT    src
            Modifies flags: None
            Loads a value from an operand into the Local Descriptor Table 
            Register (LDTR).
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16             -     17    20    11            3
            mem16             -     19    24    11            5
    
    LMSW - Load Machine Status Word (286+ privileged)
            Usage:  LMSW    src
            Modifies flags: None
            Loads the Machine Status Word (MSW) from data found at "src"
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16             -     3     10    13            3
            mem16             -     6     13    13            5
    
    LOCK - Lock Bus
            Usage:  LOCK
                    LOCK: (386+ prefix)
            Modifies flags: None
            This instruction is a prefix that causes the CPU assert bus lock
            signal during the execution of the next instruction.  Used to
            avoid two processors from updating the same data location.  The
            286 always asserts lock during an XCHG with memory operands.  This
            should only be used to lock the bus prior to XCHG, MOV, IN and
            OUT instructions.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              2     0     0     1             1
    
    LODS - Load String (Byte, Word or Double)
            Usage:  LODS    src
                    LODSB
                    LODSW
                    LODSD  (386+)
            Modifies flags: None
            Transfers string element addressed by DS:SI (even if an operand is
            supplied) to the accumulator.   SI is incremented based on the size
            of the operand or based on the instruction used.  If the Direction
            Flag is set SI is decremented, if the Direction Flag is clear SI
            is incremented.  Use with REP prefixes.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            src             12/16   5     5     5             1
    
    LOOP - Decrement CX and Loop if CX Not Zero
            Usage:  LOOP    label
            Modifies flags: None
            Decrements CX by 1 and transfers control to "label" if CX is not
            Zero.  The "label" operand must be within -128 or 127 bytes of the
            instruction following the loop instruction
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            label:  jump      18   8+m  11+m    6             2
                    no jump    5    4     ?     2
    
    LOOPE/LOOPZ - Loop While Equal / Loop While Zero
            Usage:  LOOPE   label
                    LOOPZ   label
            Modifies flags: None
            Decrements CX by 1 (without modifying the flags) and transfers
            control to "label" if CX != 0 and the Zero Flag is set.  The
            "label" operand must be within -128 or 127 bytes of the instruction
            following the loop instruction.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            label:  jump      18   8+m  11+m    9             2
                    no jump    5    4     ?     6
    
    LOOPNZ/LOOPNE - Loop While Not Zero / Loop While Not Equal
            Usage:  LOOPNZ  label
                    LOOPNE  label
            Modifies flags: None
            Decrements CX by 1 (without modifying the flags) and transfers
            control to "label" if CX != 0 and the Zero Flag is clear.  The
            "label" operand must be within -128 or 127 bytes of the instruction
            following the loop instruction.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            label:  jump      19   8+m  11+m    9             2
                    no jump    5    4     ?     6
    
    LSL - Load Segment Limit (286+ protected)
            Usage:  LSL     dest,src
            Modifies flags: ZF
            Loads the segment limit of a selector into the destination register
            if the selector is valid and visible at the current privilege level.
            If loading is successful the Zero Flag is set, otherwise it is
            cleared.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16,reg16       -     14  20/25   10            3
            reg32,reg32       -     -   20/25   10            3
            reg16,mem16       -     16  21/26   10            5
            reg32,mem32       -     -   21/26   10            5
            - 386 times are listed "byte granular" / "page granular"
    
    LSS - Load Pointer Using SS (386+)
            Usage:  LSS     dest,src
            Modifies flags: None
            Loads 32-bit pointer from memory source to destination register
            and SS.  The offset is placed in the destination register and the
            segment is placed in SS.  To use this instruction the word at the
            lower memory address must contain the offset and the word at the
            higher address must contain the segment.  This simplifies the loading
            of far pointers from the stack and the interrupt vector table.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,mem           -     -     7     6            5-7
            reg,mem (PM)      -     -     22    12           5-7
    
    LTR - Load Task Register (286+ privileged)
            Usage:  LTR     src
            Modifies flags: None
            Loads the current task register with the value specified in "src".
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16             -     17    23    20            3
            mem16             -     19    27    20            5
    
    MOV - Move Byte or Word
            Usage:  MOV     dest,src
            Modifies flags: None
            Copies byte or word from the source operand to the destination
            operand.  If the destination is SS interrupts are disabled except
            on early buggy 808x CPUs.  Some CPUs disable interrupts if the
            destination is any of the segment registers
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,reg           2     2     2     1             2
            mem,reg          9+EA   3     2     1            2-4  (W88=13+EA)
            reg,mem          8+EA   5     4     1            2-4  (W88=12+EA)
            mem,immed       10+EA   3     2     1            3-6  (W88=14+EA)
            reg,immed         4     2     2     1            2-3
            mem,accum         10    3     2     1             3   (W88=14)
            accum,mem         10    5     4     1             3   (W88=14)
            segreg,reg16      2     2     2     3             2
            segreg,mem16     8+EA   5     5     9            2-4  (W88=12+EA)
            reg16,segreg      2     2     2     3             2
            mem16,segreg     9+EA   3     2     3            2-4  (W88=13+EA)
            reg32,CR0/CR2/CR3 -     -     6     4
            CR0,reg32         -     -     10    16
            CR2,reg32         -     -     4     4             3
            CR3,reg32         -     -     5     4             3
            reg32,DR0/DR1/DR2/DR3   -     22   10             3
            reg32,DR6/DR7     -     -     22   10             3
            DR0/DR1/DR2/DR3,reg32   -     22   11             3
            DR6/DR7,reg32     -     -     16   11             3
            reg32,TR6/TR7     -     -     12    4             3
            TR6/TR7,reg32     -     -     12    4             3
            reg32,TR3                           3
            TR3,reg32                           6
            - when the 386 special registers are used all operands are 32 bits
    
    MOVS - Move String (Byte or Word)
            Usage:  MOVS    dest,src
                    MOVSB
                    MOVSW
                    MOVSD  (386+)
            Modifies flags: None
            Copies data from addressed by DS:SI (even if operands are given) to
            the location ES:DI destination and updates SI and DI based on the
            size of the operand or instruction used.  SI and DI are incremented
            when the Direction Flag is cleared and decremented when the Direction
            Flag is Set.  Use with REP prefixes.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            dest,src          18    5     7     7             1   (W88=26)
    
    MOVSX - Move with Sign Extend (386+)
            Usage:  MOVSX   dest,src
            Modifies flags: None
            Copies the value of the source operand to the destination register
            with the sign extended.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,reg           -     -     3     3             3
            reg,mem           -     -     6     3            3-7
    
    MOVZX - Move with Zero Extend (386+)
            Usage:  MOVZX   dest,src
            Modifies flags: None
            Copies the value of the source operand to the destination register
            with the zeroes extended.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,reg           -     -     3     3             3
            reg,mem           -     -     6     3            3-7
    
    MUL - Unsigned Multiply
            Usage:  MUL     src
            Modifies flags: CF OF (AF,PF,SF,ZF undefined)
            Unsigned multiply of the accumulator by the source.  If "src" is
            a byte value, then AL is used as the other multiplicand and the
            result is placed in AX.  If "src" is a word value, then AX is
            multiplied by "src" and DX:AX receives the result.  If "src" is
            a double word value, then EAX is multiplied by "src" and EDX:EAX
            receives the result.  The 386+ uses an early out algorithm which
            makes multiplying any size value in EAX as fast as in the 8 or 16
            bit registers.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8            70-77   13   9-14  13-18          2
            reg16          118-113  21   9-22  13-26          2
            reg32             -     -    9-38  13-42         2-4
            mem8        (76-83)+EA  16  12-17  13-18         2-4
            mem16     (124-139)+EA  24  12-25  13-26         2-4
            mem32             -     -   12-21  13-42         2-4
    
    NEG - Two's Complement Negation
            Usage:  NEG     dest
            Modifies flags: AF CF OF PF SF ZF
            Subtracts the destination from 0 and saves the 2s complement of
            "dest" back into "dest".
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg               3     2     2     1             2
            mem             16+EA   7     6     3            2-4  (W88=24+EA)
    
    NOP - No Operation (90h)
            Usage:  NOP
            Modifies flags: None
            This is a do nothing instruction.  It results in occupation of both
            space and time and is most useful for patching code segments.
            (This is the original XCHG AL,AL instruction)
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              3     3     3     1             1
    
    NOT - One's Compliment Negation (Logical NOT)
            Usage:  NOT     dest
            Modifies flags: None
            Inverts the bits of the "dest" operand forming the 1s complement.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg               3     2     2     1             2
            mem             16+EA   7     6     3            2-4  (W88=24+EA)
    
    OR - Inclusive Logical OR
            Usage:  OR      dest,src
            Modifies flags: CF OF PF SF ZF (AF undefined)
            Logical inclusive OR of the two operands returning the result in
            the destination.  Any bit set in either operand will be set in the
            destination.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,reg           3     2     2     1             2
            mem,reg         16+EA   7     7     3            2-4  (W88=24+EA)
            reg,mem          9+EA   7     6     2            2-4  (W88=13+EA)
            reg,immed         4     3     2     1            3-4
            mem8,immed8     17+EA   7     7     3            3-6
            mem16,immed16   25+EA   7     7     3            3-6
            accum,immed       4     3     2     1            2-3
    
    OUT - Output Data to Port
            Usage:  OUT     port,accum
            Modifies flags: None
            Transfers byte in AL,word in AX or dword in EAX to the specified
            hardware port address.  If the port number is in the range of 0-255
            it can be specified as an immediate.  If greater than 255 then the
            port number must be specified in DX.  Since the PC only decodes 10
            bits of the port address, values over 1023 can only be decoded by
            third party vendor equipment and also map to the port range 0-1023.
                                     Clocks                 Size
            Operands         808x  286   386    486         Bytes
            immed8,accum    10/14   3     10     16           2
            immed8,accum (PM) -     -    4/24 11/31/29        2
            DX,accum         8/12   3     11     16           1
            DX,accum (PM)     -     -    5/25 10/30/29        1
            - 386+ protected mode timings depend on privilege levels.
              first number is the timing when:    CPL ≤ IOPL
              second number is the timing when:   CPL > IOPL
              third number is the timing when:    virtual mode on 486 processor
    
    OUTS - Output String to Port (80188+)
            Usage:  OUTS    port,src
                    OUTSB
                    OUTSW
                    OUTSD   (386+)
            Modifies flags: None
            Transfers a byte, word or doubleword from "src" to the hardware
            port specified in DX.  For instructions with no operands the "src"
            is located at DS:SI and SI is incremented or decremented by the
            size of the operand or the size dictated by the instruction format.
            When the Direction Flag is set SI is decremented, when clear, SI is
            incremented.  If the port number is in the range of 0-255 it can
            be specified as an immediate.  If greater than 255 then the port
            number must be specified in DX.  Since the PC only decodes 10 bits
            of the port address, values over 1023 can only be decoded by third
            party vendor equipment and also map to the port range 0-1023.
                                     Clocks                 Size
            Operands         808x  286   386    486         Bytes
            port,src          -     5     14     17           1
            port,src (PM)     -     -    8/28 10/32/30        1
            - 386+ protected mode timings depend on privilege levels.
              first number is the timing when:    CPL ≤ IOPL
              second number is the timing when:   CPL > IOPL
              third number is the timing when:    virtual mode on 486 processor
    
    POP - Pop Word off Stack
            Usage:  POP     dest
            Modifies flags: None
            Transfers word at the current stack top (SS:SP) to the destination
            then increments SP by two to point to the new stack top.  CS is not
            a valid destination.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16             8     5     4     4             1
            reg32             4     -     -     4             1
            segreg            8     5     7     3             1
            mem16           17+EA   5     5     6            2-4
            mem32             5     -     -     6            2-4
    
    POPA/POPAD - Pop All Registers onto Stack (80188+)
            Usage:  POPA
                    POPAD  (386+)
            Modifies flags: None
            Pops the top 8 words off the stack into the 8 general purpose 16/32
            bit registers.   Registers are popped in the following order: (E)DI,
            (E)SI, (E)BP, (E)SP, (E)DX, (E)CX and (E)AX.  The (E)SP value popped
            from the stack is actually discarded.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              -     19    24    9             1
    
    POPF/POPFD - Pop Flags off Stack
            Usage:  POPF
                    POPFD  (386+)
            Modifies flags: all flags
            Pops word/doubleword from stack into the Flags Register and then
            increments SP by 2 (for POPF) or 4 (for POPFD).
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none             8/12   5     5     9             1  (W88=12)
            none  (PM)        -     -     5     6             1
    
    PUSH - Push Word onto Stack
            Usage:  PUSH    src
                    PUSH    immed   (80188+ only)
            Modifies flags: None
            Decrements SP by the size of the operand (two or four, byte values
            are sign extended) and transfers one word from source to the stack
            top (SS:SP).
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16           11/15   3     2     1             1
            reg32             -     -     2     1             1
            mem16           16+EA   5     5     4            2-4  (W88=24+EA)
            mem32             -     -     5     4            2-4
            segreg          10/14   3     2     3             1
            immed             -     3     2     1            2-3
    
    PUSHA/PUSHAD - Push All Registers onto Stack (80188+)
            Usage:  PUSHA
                    PUSHAD  (386+)
            Modifies flags: None
            Pushes all general purpose registers onto the stack in the following
            order: (E)AX, (E)CX, (E)DX, (E)BX, (E)SP, (E)BP, (E)SI, (E)DI.  The
            value of SP is the value before the actual push of SP.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              -     19    24    11            1
    
    PUSHF/PUSHFD - Push Flags onto Stack
            Usage:  PUSHF
                    PUSHFD  (386+)
            Modifies flags: None
            Transfers the Flags Register onto the stack.  PUSHF saves a 16 bit
            value while PUSHFD saves a 32 bit value.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none            10/14   3     4     4             1
            none  (PM)        -     -     4     3             1
    
    RCL - Rotate Through Carry Left
            Usage:  RCL     dest,count
            Modifies flags: CF OF
               +-+     +---------------+
            +-+|C|<+--+|7 <---------- 0|<-+
            |  +-+     +---------------+  |
            +-----------------------------+
            Rotates the bits in the destination to the left "count" times with
            all data pushed out the left side re-entering on the right.  The
            Carry Flag holds the last bit rotated out.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,1             2     2     9     3            2
            mem,1           15+EA   7     10    4           2-4  (W88=23+EA)
            reg,CL           8+4n  5+n    9    8-30          2
            mem,CL        20+EA+4n 8+n    10   9-31         2-4  (W88=28+EA+4n)
            reg,immed8        -    5+n     9   8-30          3
            mem,immed8        -    8+n    10   9-31         3-5
    
    RCR - Rotate Through Carry Right
            Usage:  RCR     dest,count
            Modifies flags: CF OF
               +---------------+     +-+
            +->|7 +---------> 0|+--->|C|+-+
            |  +---------------+     +-+  |
            +-----------------------------+
            Rotates the bits in the destination to the right "count" times with
            all data pushed out the right side re-entering on the left.  The
            Carry Flag holds the last bit rotated out.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,1             2     2     9     3            2
            mem,1           15+EA   7     10    4           2-4   (W88=23+EA)
            reg,CL           8+4n  5+n    9    8-30          2
            mem,CL        20+EA+4n 8+n    10   9-31         2-4   (W88=28+EA+4n)
            reg,immed8        -    5+n    9    8-30          3
            mem,immed8        -    8+n    10   9-31         3-5
    
    REP - Repeat String Operation
            Usage:  REP
            Modifies flags: None
            Repeats execution of string instructions while CX != 0.  After
            each string operation, CX is decremented and the Zero Flag is
            tested.  The combination of a repeat prefix and a segment override
            on CPU's before the 386 may result in errors if an interrupt occurs
            before CX=0.  The following code shows code that is susceptible to
            this and how to avoid it:
             again:  rep movs  byte ptr ES:[DI],ES:[SI]   ; vulnerable instr.
                         jcxz  next              ; continue if REP successful
                         loop  again             ; interrupt goofed count
             next:
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              2     2     2                   1
    
    REPE/REPZ - Repeat Equal / Repeat Zero
            Usage:  REPE
                    REPZ
            Modifies flags: None
            Repeats execution of string instructions while CX != 0 and the Zero
            Flag is set.  CX is decremented and the Zero Flag tested after
            each string operation.   The combination of a repeat prefix and a
            segment override on processors other than the 386 may result in
            errors if an interrupt occurs before CX=0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              2     2     2                   1
    
    REPNE/REPNZ - Repeat Not Equal / Repeat Not Zero
            Usage:  REPNE
                    REPNZ
            Modifies flags: None
            Repeats execution of string instructions while CX != 0 and the Zero
            Flag is clear.   CX is decremented and the Zero Flag tested after
            each string operation.   The combination of a repeat prefix and a
            segment override on processors other than the 386 may result in
            errors if an interrupt occurs before CX=0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              2     2     2                   1
    
    RET/RETF - Return From Procedure
            Usage:  RET     nBytes
                    RETF    nBytes
                    RETN    nBytes
            Modifies flags: None
            Transfers control from a procedure back to the instruction address
            saved on the stack.  "n bytes" is an optional number of bytes to
            release.  Far returns pop the IP followed by the CS, while near
            returns pop only the IP register.
                                     Clocks                 Size
            Operands         808x  286    386   486         Bytes
            retn            16/20  11+m  10+m    5            1
            retn immed      20/24  11+m  10+m    5            3
            retf            26/34  15+m  18+m    13           1
            retf (PM, same priv.)   -    32+m    18           1
            retf (PM, lesser priv.) -      68    33           1
            retf immed      25/33  15+m  18+m    14           3
            retf immed (PM, same priv.)  32+m    17           1
            retf immed (PM, lesser priv.)  68    33           1
    
    ROL - Rotate Left
            Usage:  ROL     dest,count
            Modifies flags: CF OF
            +-+     +---------------+
            |C|<++-+|7 <---------- 0|<-+
            +-+  |  +---------------+  |
                 +---------------------+
            Rotates the bits in the destination to the left "count" times with
            all data pushed out the left side re-entering on the right.  The
            Carry Flag will contain the value of the last bit rotated out.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,1             2     2     3     3             2
            mem,1           15+EA   7     7     4            2-4  (W88=23+EA)
            reg,CL           8+4n  5+n    3     3             2
            mem,CL        20+EA+4n 8+n    7     4            2-4  (W88=28+EA+4n)
            reg,immed8        -    5+n    3     2             3
            mem,immed8        -    8+n    7     4            3-5
    
    ROR - Rotate Right
            Usage:  ROR     dest,count
            Modifies flags: CF OF
               +---------------+     +-+
            +->|7 +---------> 0|+-+->|C|   
            |  +---------------+  |  +-+   
            +---------------------+        
            Rotates the bits in the destination to the right "count" times with
            all data pushed out the right side re-entering on the left.  The
            Carry Flag will contain the value of the last bit rotated out.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,1             2     2     3     3             2
            mem,1           15+EA   7     7     4            2-4  (W88=23+EA)
            reg,CL           8+4n  5+n    3     3             2
            mem,CL        20+EA+4n 8+n    7     4            2-4  (W88=28+EA+4n)
            reg,immed8        -    5+n    3     2             3
            mem,immed8        -    8+n    7     4            3-5
    
    SAHF - Store AH Register into FLAGS
            Usage:  SAHF
            Modifies flags: AF CF PF SF ZF
            Transfers bits 0-7 of AH into the Flags Register.  This includes
            AF, CF, PF, SF and ZF.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              4     2     3     2             1
    
    SAL/SHL - Shift Arithmetic Left / Shift Logical Left
            Usage:  SAL     dest,count
                    SHL     dest,count
            Modifies flags: CF OF PF SF ZF (AF undefined)
            +-+     +---------------+     +-+
            |C|<---+|7 <---------- 0|<---+|0|
            +-+     +---------------+     +-+
            Shifts the destination left by "count" bits with zeroes shifted
            in on right.  The Carry Flag contains the last bit shifted out.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,1             2     2     3     3            2
            mem,1           15+EA   7     7     4           2-4  (W88=23+EA)
            reg,CL           8+4n  5+n    3     3            2
            mem,CL        20+EA+4n 8+n    7     4           2-4  (W88=28+EA+4n)
            reg,immed8        -    5+n    3     2            3
            mem,immed8        -    8+n    7     4           3-5
    
    SAR - Shift Arithmetic Right
            Usage:  SAR     dest,count
            Modifies flags: CF OF PF SF ZF (AF undefined)
               +---------------+     +-+
            +-+|7 ----------> 0|---+>|C|
            |  +---------------+     +-+
            +---^
            Shifts the destination right by "count" bits with the current sign
            bit replicated in the leftmost bit.  The Carry Flag contains the
            last bit shifted out.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,1             2     2     3     3             2
            mem,1           15+EA   7     7     4            2-4  (W88=23+EA)
            reg,CL           8+4n  5+n    3     3             2
            mem,CL        20+EA+4n 8+n    7     4            2-4  (W88=28+EA+4n)
            reg,immed8        -    5+n    3     2             3
            mem,immed8        -    8+n    7     4            3-5
    
    SBB - Subtract with Borrow/Carry
            Usage:  SBB     dest,src
            Modifies flags: AF CF OF PF SF ZF
            Subtracts the source from the destination, and subtracts 1 extra if
            the Carry Flag is set.   Results are returned in "dest".
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,reg           3     2     2     1             2
            mem,reg         16+EA   7     6     3            2-4  (W88=24+EA)
            reg,mem          9+EA   7     7     2            2-4  (W88=13+EA)
            reg,immed         4     3     2     1            3-4
            mem,immed       17+EA   7     7     3            3-6  (W88=25+EA)
            accum,immed       4     3     2     1            2-3
    
    SCAS - Scan String (Byte, Word or Doubleword)
            Usage:  SCAS    string
                    SCASB
                    SCASW
                    SCASD   (386+)
            Modifies flags: AF CF OF PF SF ZF
            Compares value at ES:DI (even if operand is specified) from the
            accumulator and sets the flags similar to a subtraction.  DI is
            incremented/decremented based on the instruction format (or
            operand size) and the state of the Direction Flag.  Use with REP
            prefixes.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            string            15    7     7     6             1  (W88=19)
    
    SETAE/SETNB - Set if Above or Equal / Set if Not Below (386+)
            Usage:  SETAE   dest
                    SETNB   dest
            (unsigned, 386+)
            Modifies flags: none
            Sets the byte in the operand to 1 if the Carry Flag is clear
            otherwise sets the operand to 0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              -     -     4     3             3
            mem8              -     -     5     4             3
    
    SETB/SETNAE - Set if Below / Set if Not Above or Equal (386+)
            Usage:  SETB    dest
                    SETNAE  dest
            (unsigned, 386+)
            Modifies flags: none
            Sets the byte in the operand to 1 if the Carry Flag is set
            otherwise sets the operand to 0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              -     -     4     3             3
            mem8              -     -     5     4             3
    
    SETBE/SETNA - Set if Below or Equal / Set if Not Above (386+)
            Usage:  SETBE   dest
                    SETNA   dest
            (unsigned, 386+)
            Modifies flags: none
            Sets the byte in the operand to 1 if the Carry Flag or the Zero
            Flag is set, otherwise sets the operand to 0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              -     -     4     3             3
            mem8              -     -     5     4             3
    
    SETE/SETZ - Set if Equal / Set if Zero (386+)
            Usage:  SETE    dest
                    SETZ    dest
            Modifies flags: none
            Sets the byte in the operand to 1 if the Zero Flag is set,
            otherwise sets the operand to 0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              -     -     4     3             3
            mem8              -     -     5     4             3
    
    SETNE/SETNZ - Set if Not Equal / Set if Not Zero (386+)
            Usage:  SETNE   dest
                    SETNZ   dest
            Modifies flags: none
            Sets the byte in the operand to 1 if the Zero Flag is clear,
            otherwise sets the operand to 0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              -     -     4     3             3
            mem8              -     -     5     4             3
    
    SETL/SETNGE - Set if Less / Set if Not Greater or Equal (386+)
            Usage:  SETL    dest
                    SETNGE  dest
            (signed, 386+)
            Modifies flags: none
            Sets the byte in the operand to 1 if the Sign Flag is not equal
            to the Overflow Flag, otherwise sets the operand to 0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              -     -     4     3             3
            mem8              -     -     5     4             3
    
    SETGE/SETNL - Set if Greater or Equal / Set if Not Less (386+)
            Usage:  SETGE   dest
                    SETNL   dest
            (signed, 386+)
            Modifies flags: none
            Sets the byte in the operand to 1 if the Sign Flag equals the
            Overflow Flag, otherwise sets the operand to 0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              -     -     4     3             3
            mem8              -     -     5     4             3
    
    SETLE/SETNG - Set if Less or Equal / Set if Not greater or Equal (386+)
            Usage:  SETLE   dest
                    SETNG   dest
            (signed, 386+)
            Modifies flags: none
            Sets the byte in the operand to 1 if the Zero Flag is set or the
            Sign Flag is not equal to the Overflow Flag,  otherwise sets the
            operand to 0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              -     -     4     3             3
            mem8              -     -     5     4             3
    
    SETG/SETNLE - Set if Greater / Set if Not Less or Equal (386+)
            Usage:  SETG    dest
                    SETNLE  dest
            (signed, 386+)
            Modifies flags: none
            Sets the byte in the operand to 1 if the Zero Flag is clear or the
            Sign Flag equals to the Overflow Flag,  otherwise sets the operand
            to 0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              -     -     4     3             3
            mem8              -     -     5     4             3
    
    SETS - Set if Signed (386+)
            Usage:  SETS    dest
            Modifies flags: none
            Sets the byte in the operand to 1 if the Sign Flag is set, otherwise
            sets the operand to 0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              -     -     4     3             3
            mem8              -     -     5     4             3
    
    SETNS - Set if Not Signed (386+)
            Usage:  SETNS   dest
            Modifies flags: none
            Sets the byte in the operand to 1 if the Sign Flag is clear,
            otherwise sets the operand to 0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              -     -     4     3             3
            mem8              -     -     5     4             3
    
    SETC - Set if Carry (386+)
            Usage:  SETC    dest
            Modifies flags: none
            Sets the byte in the operand to 1 if the Carry Flag is set,
            otherwise sets the operand to 0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              -     -     4     3             3
            mem8              -     -     5     4             3
    
    SETNC - Set if Not Carry (386+)
            Usage:  SETNC   dest
            Modifies flags: none
            Sets the byte in the operand to 1 if the Carry Flag is clear,
            otherwise sets the operand to 0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              -     -     4     3             3
            mem8              -     -     5     4             3
    
    SETO - Set if Overflow (386+)
            Usage:  SETO    dest
            Modifies flags: none
            Sets the byte in the operand to 1 if the Overflow Flag is set,
            otherwise sets the operand to 0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              -     -     4     3             3
            mem8              -     -     5     4             3
    
    SETNO - Set if Not Overflow (386+)
            Usage:  SETNO   dest
            Modifies flags: none
            Sets the byte in the operand to 1 if the Overflow Flag is clear,
            otherwise sets the operand to 0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              -     -     4     3             3
            mem8              -     -     5     4             3
    
    SETP/SETPE - Set if Parity / Set if Parity Even (386+)
            Usage:  SETP    dest
                    SETPE   dest
            Modifies flags: none
            Sets the byte in the operand to 1 if the Parity Flag is set,
            otherwise sets the operand to 0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              -     -     4     3             3
            mem8              -     -     5     4             3
    
    SETNP/SETPO - Set if No Parity / Set if Parity Odd (386+)
            Usage:  SETNP   dest
                    SETPO   dest
            Modifies flags: none
            Sets the byte in the operand to 1 if the Parity Flag is clear,
            otherwise sets the operand to 0.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg8              -     -     4     3             3
            mem8              -     -     5     4             3
    
    SGDT - Store Global Descriptor Table (286+ privileged)
            Usage:  SGDT    dest
            Modifies flags: none
            Stores the Global Descriptor Table (GDT) Register into the
            specified operand.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            mem64             -     11    9     10            5
    
    SIDT - Store Interrupt Descriptor Table (286+ privileged)
            Usage:  SIDT    dest
            Modifies flags: none
            Stores the Interrupt Descriptor Table (IDT) Register into the
            specified operand.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            mem64             -     12    9     10            5
    
    SHL - Shift Logical Left
            See: SAL
    
    SHR - Shift Logical Right
            Usage:  SHR     dest,count
            Modifies flags: CF OF PF SF ZF (AF undefined)
            +-+     +---------------+     +-+
            |0|---+>|7 ----------> 0|---+>|C|
            +-+     +---------------+     +-+
            Shifts the destination right by "count" bits with zeroes shifted
            in on the left.  The Carry Flag contains the last bit shifted out.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,1             2     2     3                   2
            mem,1           15+EA   7     7                  2-4   (W88=23+EA)
            reg,CL           8+4n  5+n    3                   2
            mem,CL        20+EA+4n 8+n    7                  2-4   (W88=28+EA+4n)
            reg,immed8        -    5+n    3                   3
            mem,immed8        -    8+n    7                  3-5
    
    SHLD/SHRD - Double Precision Shift (386+)
            Usage:  SHLD    dest,src,count
                    SHRD    dest,src,count
            Modifies flags: CF PF SF ZF (OF,AF undefined)
            SHLD shifts "dest" to the left "count" times and the bit positions
            opened are filled with the most significant bits of "src".  SHRD
            shifts "dest" to the right "count" times and the bit positions
            opened are filled with the least significant bits of the second
            operand.  Only the 5 lower bits of "count" are used.
                                            Clocks                  Size
            Operands                808x  286   386   486           Bytes
            reg16,reg16,immed8       -     -     3     2              4
            reg32,reg32,immed8       -     -     3     2              4
            mem16,reg16,immed8       -     -     7     3              6
            mem32,reg32,immed8       -     -     7     3              6
            reg16,reg16,CL           -     -     3     3              3
            reg32,reg32,CL           -     -     3     3              3
            mem16,reg16,CL           -     -     7     4              5
            mem32,reg32,CL           -     -     7     4              5
    
    SLDT - Store Local Descriptor Table (286+ privileged)
            Usage:  SLDT    dest
            Modifies flags: none
            Stores the Local Descriptor Table (LDT) Register into the
            specified operand.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16             -     2     2     2             3
            mem16             -     2     2     3             5
    
    SMSW - Store Machine Status Word (286+ privileged)
            Usage:  SMSW    dest
            Modifies flags: none
            Store Machine Status Word (MSW) into "dest".
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16             -     2     10    2             3
            mem16             -     3     3     3             5
    
    STC - Set Carry
            Usage:  STC
            Modifies flags: CF
            Sets the Carry Flag to 1.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              2     2     2     2             1
    
    STD - Set Direction Flag
            Usage:  STD
            Modifies flags: DF
            Sets the Direction Flag to 1 causing string instructions to
            auto-decrement SI and DI instead of auto-increment.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              2     2     2     2             1
    
    STI - Set Interrupt Flag (Enable Interrupts)
            Usage:  STI
            Modifies flags: IF
            Sets the Interrupt Flag to 1, which enables recognition of all
            hardware interrupts.  If an interrupt is generated by a hardware
            device, an End of Interrupt (EOI) must also be issued to enable
            other hardware interrupts of the same or lower priority.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              2     2     2     5             1
    
    STOS - Store String (Byte, Word or Doubleword)
            Usage:  STOS    dest
                    STOSB
                    STOSW
                    STOSD
            Modifies flags: None
            Stores value in accumulator to location at ES:(E)DI (even if operand
            is given).  (E)DI is incremented/decremented based on the size of
            the operand (or instruction format) and the state of the Direction
            Flag.   Use with REP prefixes.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            dest              11    3     4     5             1  (W88=15)
    
    STR - Store Task Register (286+ privileged)
            Usage:  STR     dest
            Modifies flags: None
            Stores the current Task Register to the specified operand.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16             -     2     2     2             3
            mem16             -     3     2     3             5
    
    SUB - Subtract
            Usage:  SUB     dest,src
            Modifies flags: AF CF OF PF SF ZF
            The source is subtracted from the destination and the result is
            stored in the destination.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,reg           3     2     2     1             2
            mem,reg         16+EA   7     6     3            2-4  (W88=24+EA)
            reg,mem          9+EA   7     7     2            2-4  (W88=13+EA)
            reg,immed         4     3     2     1            3-4
            mem,immed       17+EA   7     7     3            3-6  (W88=25+EA)
            accum,immed       4     3     2     1            2-3
    
    TEST - Test For Bit Pattern
            Usage:  TEST    dest,src
            Modifies flags: CF OF PF SF ZF (AF undefined)
            Performs a logical AND of the two operands updating the flags
            register without saving the result.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,reg           3     2     1     1             2
            reg,mem          9+EA   6     5     1            2-4  (W88=13+EA)
            mem,reg          9+EA   6     5     2            2-4  (W88=13+EA)
            reg,immed         5     3     2     1            3-4
            mem,immed       11+EA   6     5     2            3-6
            accum,immed       4     3     2     1            2-3
    
    VERR - Verify Read (286+ protected)
            Usage:  VERR    src
            Modifies flags: ZF
            Verifies the specified segment selector is valid and is readable
            at the current privilege level.  If the segment is readable,
            the Zero Flag is set, otherwise it is cleared.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16             -     14    10    11            3
            mem16             -     16    11    11            5
    
    VERW - Verify Write (286+ protected)
            Usage:  VERW    src
            Modifies flags: ZF
            Verifies the specified segment selector is valid and is ratable
            at the current privilege level.  If the segment is writable,
            the Zero Flag is set, otherwise it is cleared.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg16             -     14    15    11            3
            mem16             -     16    16    11            5
    
    WAIT/FWAIT - Event Wait
            Usage:  WAIT
                    FWAIT
            Modifies flags: None
            CPU enters wait state until the coprocessor signals it has finished
            its operation.  This instruction is used to prevent the CPU from
            accessing memory that may be temporarily in use by the coprocessor.
            WAIT and FWAIT are identical.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              4     3     6+   1-3            1
    
    WBINVD - Write-Back and Invalidate Cache (486+)
            Usage:  WBINVD
            Modifies flags: None
            Flushes internal cache, then signals the external cache to write
            back current data followed by a signal to flush the external cache.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            none              -     -     -     5             2
    
    XCHG - Exchange
            Usage:  XCHG    dest,src
            Modifies flags: None
            Exchanges contents of source and destination.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,reg           4     3     3     3             2
            mem,reg         17+EA   5     5     5            2-4  (W88=25+EA)
            reg,mem         17+EA   5     5     3            2-4  (W88=25+EA)
            accum,reg         3     3     3     3             1
            reg,accum         3     3     3     3             1
    
    XLAT/XLATB - Translate
            Usage:  XLAT    translation-table
                    XLATB   (masm 5.x)
            Modifies flags: None
            Replaces the byte in AL with byte from a user table addressed by
            BX.  The original value of AL is the index into the translate table.
            The best way to discripe this is MOV AL,[BX+AL]
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            table offset      11    5     5     4             1
    
    XOR - Exclusive OR
            Usage:  XOR     dest,src
            Modifies flags: CF OF PF SF ZF (AF undefined)
            Performs a bitwise exclusive OR of the operands and returns
            the result in the destination.
                                     Clocks                 Size
            Operands         808x  286   386   486          Bytes
            reg,reg           3     2     2     1             2
            mem,reg         16+EA   7     6     3            2-4  (W88=24+EA)
            reg,mem          9+EA   7     7     2            2-4  (W88=13+EA)
            reg,immed         4     3     2     1            3-4
            mem,immed       17+EA   7     7     3            3-6  (W88=25+EA)
            accum,immed       4     3     2     1            2-3

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