سلام
شاید این کمک بکنه ...
page 100,100
title swap string
CR EQU 0DH
LF EQU 10
.model small
.data
string db 'assembly',cr,lf,'$'
stringlength dw 08
stringrevers db 'abcdefgh' , '$'
.code
main proc far
mov ax, @data
mov ds, ax
mov cx, stringlength
lea si, string
lea di, stringrevers
L1:
mov al, [si]
mov ah, [di]
xchg [si], ah
xchg [di], al
inc si
inc di
loop L1
mov ah, 09h
lea dx, string
int 21h
mov ah, 09h
lea dx, stringrevers
int 21h
mov ax, 4c00h
int 21h
main endp
end main