The Intel 8086 / 8088/ 80186 / 80286 / 80386 / 80486 Instruction Set
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L Instructions

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
Timing:
Clocks
operands 		286 386 486 Size in Bytes
none 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.
Timing:
Clocks operands 286 386 486 Size 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

LEA - Load Effective Address 
      Usage: LEA dest,src

      Modifies Flags: None

      Transfers offset address of "src" to the destination register.
Timing:
Clocks operands 286 386 486 Size Bytes
reg,mem 3 2 1 2-4

LEAVE - Restore Stack for Procedure Exit (80188+) 
      Usage: LEAVE

      Modifies Flags: LEAVE

      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.
Timing:
Clocks operands 286 386 486 Size 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.
Timing:
Clocks operands 286 386 486 Size Bytes
reg,mem 7 7 6 2-4
reg,mem (PM) 22 12 5-7

LFS - Load Pointer Using FS 
      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.
Timing:
Clocks operands 286 386 486 Size 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.
Timing:
Clocks operands 286 386 486 Size Bytes
mem64 11 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.
Timing:
Clocks operands 286 386 486 Size Bytes
reg,mem 7 6 5-7
reg,mem (PM) 22 12 5-7

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.
Timing:
Clocks operands 286 386 486 Size Bytes
mem64 12 11 11 5

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).
Timing:
Clocks operands 286 386 486 Size 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".
Timing:
Clocks operands 286 386 486 Size 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.
Timing:
Clocks operands 286 386 486 Size Bytes
none 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.
Timing:
Clocks operands 286 386 486 Size Bytes
src 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
Timing:
Clocks operands 286 386 486 Size Bytes
label: jump 8+m 11+m 6 2
no jump 4 ? 2 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.
Timing:
Clocks operands 286 386 486 Size Bytes
label: jump 8+m 11+m 9 2
no jump 4 ? 6 2 

LOOPNE/LOOPNZ - Loop While Not Equal / Loop While Not Zero

      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.
Timing:
Clocks operands 286 386 486 Size Bytes
label: jump 8+m 11+m 9 2
no jump 4 ? 6 2

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.
Timing:
Clocks operands 286 386 486 Size 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.
Timing:
Clocks operands 286 386 486 Size 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".
Timing:
Clocks operands 286 386 486 Size Bytes
reg16 17 23 20 3
mem16 19 27 20 5

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