I have ported the kernel MCX11 to MCX12 in order to use it with the MC9S12 microcontrollers family. Visit the GCC2MCX12 page at:
http://perso.orange.fr/jean-michel.roux/68HC12/gcc2mcx12.
GCC2MCX11 revision 3 is also available at:
http://perso.orange.fr/jean-michel.roux/68HC11/gcc2mcx11.