LDS - Load Far Pointer Instruction

The LDS instruction is used to load (read) a segment and Far address from a memory location 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 and a 16 bit offset address.

LDS loads the offset address into the Register provided in the first operand, then the Segment into the DS Register.

Breakdown Description 16bit Machine
Code

LDS ; Instruction C5

SI ; Register for the offset address
; See below

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

DataAddress ; A Label address

LDS 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

LDS SI, [BX] ; Call LDS

Alternate method

Assembly
Sample Description

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

PUSH BX

POP DS

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

Assembly
Sample Description 16 bit Machine
Code

LDS SI, [BX] ; Load DS and SI from the memory
; address in [BX] C5 33

Breakdown	Description	16bit Machine Code
LDS	; Instruction	C5
SI	; Register for the offset address ; See below
[BX]	; A memory address from [BX] ; pointed to by BX
DataAddress	; A Label 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
LDS SI, [BX]	; Call LDS

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