16 bit Assembly

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LES   - Load Far Pointer Instruction

The LES 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 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   DescriptionCode
LES ; InstructionC4h
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 SampleDescription
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 SampleDescription
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 adress in [BX] 		  C4 33



Last Update 11/02/2023