On 10/22/2012 02:56 PM, Jordi Guillaumes i Pons wrote: The main barrier to a bare metal binary, or for that matter a not so bare metal one, is the supporting libraries. I did a *really* crude hack job on newlib to give me just enough bare metal support that I could run the GCC test suite under SIMH. But that certainly isn't enough for real bare metal. A pdp11 port of newlib would be a nice project. I tried... But it is too big. I think I got a fatty library because I selected the floating point support... I tried to use sprintf() and it didn't even fit into the PDP address space :(. The printf() family is GIGANTIC. In newlib there are non-FP-enabled versions of those functions; iprintf(), siprintf(), etc. They are much, much smaller than their floating-point counterparts. I suggest you try again with that and see where things land. I'm using them on ARM7 with great results. Granted that's got a much larger address space, but my resultant binaries and stack utilization are still pretty small. The 2.11BSD lib looks leaner, and I am using it in my pet OS project (I pick the pieces I need "on the run", I have not done a complete port... yet). If the above suggestion doesn't get you anywhere, perhaps avrlibc could be hacked into a PDP-11 library. All of the hardware support will have to be ripped out of course, but there are nice tight implementations of generic library functions in there. -Dave -- Dave McGuire, AK4HZ New Kensington, PA