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B compiler

Here you can find three B compilers. One written in C and one written in B itself. Both generate the original threaded code as described here.

The state of this repo is rather chaotic right now. sorry.

B compiler in C

This compiler I wrote to bootstrap B. It is a single executable and can produce code for PDP-11, amd64, mips32 and riscv64 assemblers. It is good enough to compile bc.b and ba.b.

B compiler in B

This one is the real deal. It works in two phases. bc.b compiles a B file to an intermediate format and ba.b further processes it to assembly. Except for word size the first pass should mostly be platform independent. The second pass is assembler and to some degree platform dependent.

B for UNIX v1

Having discovered a few B binaries I set out to reconstruct the B compiler as closely as I could and get it to run on UNIX v1. You can find the result in the unix1_bdir directory.

Platforms

B has been confirmed to compile itself on the following platforms:

  • Linux amd64
  • Linux mips32 (ci20 devboard)
  • Linux riscv64
  • 2.11BSD PDP-11

TODO

  • Get rid of chaos
  • More platforms
  • make mips code work on cpus with load delay