LES - Load Far Pointer Instruction

The LES instruction is used to load (read) a segment and address from a memory address into registers. The memory address most hold the Segment and Offset address.

This command has 3 parts, Instruction, Register, and a 32 bit memory address made up of 16 bit Segment number followed by an offset from the start of it.

LES loads the Offset address into the Register provided in the first operand, then the Segment in to the ES Register.

Breakdown Description 16 bit Machine
Code

LES ; Instruction C4h

DI ; Register number

[BX] ; A memory address from [BX] pointed
; to by BX

DataAddress ; A Label address 25 C0

LES using a memory address

Assembly
Sample Description

MOV BX, 0x0345 ; Assign the memory address of the Pointer

or

MOV BX, DataAddress ; Assign the memory address of the Pointer

LES DI, [BX] ; Call LES

Alternate method

Assembly
Sample Description

MOV BX, 0x0005 ; Assign the memory address of the Pointer

PUSH BX

POP ES

MOV SI, DataAddress ; Assign the memory address of the
; Pointer to a Register

Assembly
Sample Description 16 bit Machine
Code

LES SI, [BX] ; Load ES and DI from the memory
; address in [BX] C4 33

Breakdown	Description	16 bit Machine Code
LES	; Instruction	C4h
DI	; Register number
[BX]	; A memory address from [BX] pointed ; to by BX
DataAddress	; A Label address	25 C0

Assembly Sample	Description
MOV BX, 0x0345	; Assign the memory address of the Pointer
or
MOV BX, DataAddress	; Assign the memory address of the Pointer
LES DI, [BX]	; Call LES

Assembly Sample	Description
MOV BX, 0x0005	; Assign the memory address of the Pointer
PUSH BX
POP ES
MOV SI, DataAddress	; Assign the memory address of the ; Pointer to a Register