[TUHS] B compiler restored

So there's been quite a bit of talk about B recently (mostly from my side) and right now I feel that I've reach an interesting enough milestone to warrant a separate thread for this here. First of all, I want to stress that this is still WIP, but everything can be found here now: https://github.com/aap/b/tree/master/unix1_bdir In this repo you will find the following: - bc and ba that can build themselves (I've included .s files so everything can be bootstrapped easily). - libb and bilib in source form from object/library and binary files of the s2 tape - brt1 and brt2 restored from binary files of the s2 tape - olibb, obilib and obrt1, older versions of the above - a version of ba that does not generate threaded code but an interpreted code more like the pdp-7 code. ken told me such a thing existed at one point and indeed it is the only way to fit the compiler into 8kb/4kw - an implementation of this interpreted code. With this bc and ba fit into 8kb Note I have only tested this under apout so far. The version I used [1] needed two tweaks, but see my README. With this I was able to build the recently reversed B programs [2] and produce exact matches to the originals (modulo assembler differences). In that process I found a few mistakes I made, now the programs are exact. I want to thank everyone who was of help in this endeavour in one way or another: Ken Thompson, Phil Budne, Robert Swierczek, Steve Johnson, Warren Toomey What's left to do now is to actually run this under UNIX v1 proper, preferably even on a real machine. I've been too lazy for that so far. Also there are inaccuracies and unknowns in the compiler and assembler. Right now the intermediate code is a binary code that's easy to generate and to parse, but if I understood ken correctly the intermediate code was more like something the PDP-7 assembler could deal with. I'm also rather unsure how to handle the conditional ?: operator. The printf.o file shows that it produces labels that are in line with all the other labels. Now the C compiler uses labels starting at L10000 for the ones generated in the second pass. So it *feels* like the conditional should be generated by bc directly and not by ba but this leads to other problems, which I won't go into detail now. Finally the code should probably be a bit closer to the C compiler than it currently is. Cheers, Angelo [1] https://github.com/philbudne/pdp11-B/tree/pb/tools/apout [2] http://squoze.net/B/programs/