16 bit Assembly

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LDS   - Load Far Pointer Instruction

The LDS instruction is used to load (read) a segment and address from memory 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 DS Register.

Breakdown   DescriptionCode
LDS ; InstructionC5
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 SampleDescription
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 SampleDescription
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 adress in [BX] 		  C5 33



Last Update 11/02/2023