[TUHS] New project to recreate the B compiler for the PDP-11

Angelo Papenhoff aap at papnet.eu
Wed Apr 24 08:47:02 AEST 2019

Nice project. I wanted to do something like this too at some point.
I documented B for the PDP-7 and -11 here:
I have a partially working, sort of portable B compiler (in C) here:

Since B is so damn portable I wanted to target a bunch of architectures.
Started amd64 and pdp-8 but then other things got in a way (a VCF) and
my attention shifted.


On 23/04/19, Robert Swierczek wrote:
> I just started a project to recreate the B compiler for the PDP-11 as
> authentically as possible, given the few fragments that remain and
> some educated guesswork.  It should be fun (for various definitions of
> fun).
> Here is the repository  https://github.com/rswier/pdp11-B
> I have borrowed some tools from Warren's
> https://github.com/DoctorWkt/unix-jun72
> I have made a good start at reverse engineering the B run time library
> in /usr/lib/libb.a.  I have tried to make the source match the same
> style as the earliest C library found on the last1120c-bits tape.  The
> remaining functions in libb.a include printf and printn which appear
> to be written in B.  This should provide more clues needed to create
> the compiler.
> I am also tackling the dis-assembly of the threaded code interpreter
> /usr/lib/bilib.a (which at the moment is a big mess on my hard-drive)
> Later steps will include creating the B compiler itself by carefully
> pruning down the last1120c C compiler.  The fun here will be to
> boot-strap the B compiler without help from any existing modern
> compilers.  I think TMG will come into play to make that happen.
> All are welcome to contribute!
> Rob

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