Big-Endian on Little-Endian

In this post, I will share how I set up big-endian emulation on my little-endian Intel machine to tets a program for byte order related issues. I used the QEMU PowerPC emulator to set up the big-endian emulation. The steps to do so are documented in the list below.

1. Install QEMU.

   apt-get update && apt-get install qemu

2. Download mol-0.9.72.1.tar.bz2 from http://sourceforge.net/projects/mac-on-linux/files/ and copy the file named video.x from the downloaded tarball to /usr/share/qemu/. This is necessary to prevent qemu-system-ppc from complaining about it.

   wget https://sourceforge.net/projects/mac-on-linux/files/mac-on-linux/mol-0.9.72.1/mol-0.9.72.1.tar.bz2
   tar -xjf mol-0.9.72.1.tar.bz2
   sudo cp mol-0.9.72.1/mollib/drivers/video.x /usr/share/qemu/
   

3. Create a QEMU hard disk image.

   qemu-img create powerpc.img 2G

4. Download Debian for PowerPC and install it on the QEMU hard disk image.

   wget http://cdimage.debian.org/debian-cd/5.0.4/powerpc/iso-cd/debian-504-powerpc-CD-1.iso
   qemu-system-ppc -m 512 -boot d -hda powerpc.img -cdrom debian-504-powerpc-CD-1.iso
   

5. Boot the QEMU PowerPC emulator with the new hard disk image.

   qemu-system-ppc -m 512 -hda powerpc.img

6. Write a small program inside the new Debian system, say, endian.c like this:

   #include <stdio.h>
   
   int main()
   {
       int n = 1;
       printf(*((char *) &n) ? "little-endian\n" : "big-endian\n");
       return 0;
   }
   

7. Compile and execute the C program.

   $ gcc endian.c && ./a.out
   big-endian