.386
.model flat, stdcall
.data
bigEndian BYTE 12h, 34h, 56h, 78h
; 78 34 56 12
littleEndian DWORD ?
.code
start:
    ;write your code here
    mov al, [bigEndian+3]   ;al = 78
    mov ah, [bigEndian]     ;ah = 12
    mov [bigEndian], al     ;bigEndian {78, 34, 56, 78}
    mov [bigEndian+3], ah   ;bigEndian {78, 34, 56, 12}
    mov al, [bigEndian+2]   ;al = 56
    mov ah, [bigEndian+1]   ;ah = 34
    mov [bigEndian+1], al   ;bigEndian {78, 56, 56, 78}
    mov [bigEndian+2], ah   ;bigEndian {78, 56, 34, 78}
    ;Convertidor
    mov eax, DWORD PTR bigEndian
    ;Se le pasa el eax a la  nueva lista convertida
    mov littleEndian, eax

    ret
    END start