embedded libraries for PDP-11, was Re: [HECnet] DECUS RSX C compiler

[Dave McGuire]

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