1. Program for converting from Big Endian to Little Endian in Assembly Language using Visual Studio

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Chapter 4

Data Transfers, Addressing, and Arithmetic

Assembly Language Programming Exercise

Problem # 1:

Write a program that uses the variables below and MOV instructions to copy the value from bigEndian to littleEndian, reversing the order of the bytes. The number’s 32-bit value is understood to be 12345678 hexadecimal.
.data
bigEndian BYTE 12h,34h,56h,78h
littleEndian DWORD

Solution:

; Program Name:  bigEndian to LittleEndian

.386
.model flat,stdcall
.stack 4096
ExitProcess PROTO, dwExitCode:DWORD

.data
bigEndian BYTE 12h,34h,56h,78h
littleEndian DWORD ?

.code
main PROC
  mov al,[bigEndian+3]
  mov BYTE PTR [littleEndian],al

  mov al,[bigEndian+2]
  mov BYTE PTR [littleEndian+1],al

  mov al,[bigEndian+1]
  mov BYTE PTR [littleEndian+2],al

  mov al,[bigEndian]
  mov BYTE PTR [littleEndian+3],al

INVOKE ExitProcess,0
main ENDP
END main

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