MOVSB and MOVSW
Move Far Instruction

The MOVSB and MOVSW instructions are used to move data between segments from the address pointed to by the DS:SI register to the address of the ES:DI Register.

After each call the SI and DI Registers are incremented by one byte for BYTE operations or by two bytes for WORD.

SI and DI are decremented backwards when the direction flag is set using the STD instruction.

Unlike LODSB and LODSW it can be used to move data between sements.

This command has 1 part, the Instruction.

Assembly
Sample Description 16 bit Machine
Code

MOVSB ; 8 bit version moves BYTES from SI in to DI A4

MOVSW ; 16 bit version moves WORDS from SI in to DI A5

This example moves 16 single bytes before exiting the LOOP.

Assembly
Sample Description 16 bit Machine
Code

MOV CX, 0x0010 ; Assign 10h (16) to the Counter CX B9 10 00

MOV SI, DataString ; Assign SI to point at a memory
; location to be read. BE 26 01

MOV DI, DataOut ; Assign DI to point at a memory
; location to save in. BF 36 01

MOVSB ; Load one byte into AL A4

LOOP 0xFD ; LOOP back to LODSB to read
; each byte until CX = 0 E2 FD

Assembly Sample	Description	16 bit Machine Code
MOVSB	; 8 bit version moves BYTES from SI in to DI	A4
MOVSW	; 16 bit version moves WORDS from SI in to DI	A5

Assembly Sample	Description	16 bit Machine Code
MOV CX, 0x0010	; Assign 10h (16) to the Counter CX	B9 10 00
MOV SI, DataString	; Assign SI to point at a memory ; location to be read.	BE 26 01
MOV DI, DataOut	; Assign DI to point at a memory ; location to save in.	BF 36 01
MOVSB	; Load one byte into AL	A4
LOOP 0xFD	; LOOP back to LODSB to read ; each byte until CX = 0	E2 FD

MOVSB and MOVSWMove Far Instruction

MOVSB and MOVSW
Move Far Instruction