osaboh / lispBM

An interpreter for a lisp-like language implemented in C.

lispBM

A lisp-like language (work in progress) implemented in C for 32-bit platforms.

Purpose

1. Have fun.
2. Learn about lisp.
3. An interactive REPL for devboards.
4. ...

Features

1. heap consisting of cons-cells with mark and sweep garbage collection.
2. Built-in functions: cons, car, cdr, eval, list, +, -, >, <, = and more.
3. Some special forms: Lambdas, closures, lets (letrecs), define and quote.
4. 28-Bit signed/unsigned integers and boxed 32-Bit Float, 32-Bit signed/unsigned values.
5. Arrays (in progress), string is an array.
6. Compiles for, and runs on linux-x86 (builds 32bit library, runs on 32/64 bit).
7. Compiles for, and runs on Zynq 7000.
8. Compiles for, and runs on STM32f4.
9. Compiles for, and runs on NRF52840.
10. Compiles for, and runs on ESP32.
11. Quasiquotation (needs more testing).

Documentation

LispBM's internals are documented as a series of blog posts.

TODOs

1. (DONE) Write some tests that stresses the Garbage collector.
2. (DONE) Implement some "reference to X type", for uint32, int32.
3. (DONE) Write a small library of useful hofs.
4. (DONE) Improve handling of arguments in eval-cps.
5. (DONE) Code improvements with simplicity, clarity and readability in mind.
6. (DONE) Implement a small dedicated lisp reader/parser to replace MPC. MPC eats way to much memory for small platforms.
7. (DONE) Port to STM32f4 - 128K ram platform (will need big changes). (surely there will be some more bugs)
8. (DONE) Add STM32f4 example code (repl implementation)
9. (DONE) Port to nrf52840_pca10056 - 256k ram platform (same changes as above).
10. (DONE) Reduce size of builtins.c and put platform specific built in functions elsewhere. (Builtins.c will be removed an replaced by fundamentals.c)
11. (DONE) Implement 'progn' facility.
12. (DONE) Remove the "gensym" functionality havent found a use for it so far and it only complicates things.
13. (DONE) Add NRF52 example repl to repository
14. (DONE) Update all example REPLs after adding quasiquotation
15. Test all example REPLs after addition of quasiquotation
16. Add ESP32 example repl to repository.
17. Recursion to Iteration. Where it is possible turn recursive function calls into iterations (Implementation).
18. Test on all platforms after big changes to eval_cps.c.
19. Implement some looping structure for speed or just ease of use.
20. Be much more stringent on checking of error conditions etc.

Compile for linux (Requires 32bit libraries. May need something like "multilib" on a 64bit linux)

1. Build the library: make

2. Build the repl: cd repl-cps and then make

3. Run the repl: ./repl

Compile for Zynq devboard (bare-metal)

1. Source your vivado settings: source <PATH_TO>/settings.sh

2. Build library for ARM A9: PLATFORM=zynq make

3. Create a standalone app in Vivado SDK (helloworld template is a good starting point)

4. Go to menu: Project > Properties > Tool settings > ARM v7 gcc linker > Miscellaneous and add in OTHER OBJECTS the path to liblispbm.a (build/zynq/liblispbm.a)

5. Go to menu: Project > Properties > Tool settings > ARM v7 gcc compiler > Directories and add in INCLUDE DIRECTORIES the path to the include directory.

6. Go to menu: Project > Properties > Tool settings > ARM v7 gcc compiler > Miscellaneous and add -D_32_BIT_ to "Other flags"

7. Go to menu: Xilinx > Generate linker script and set up for enough of heap and stack. 128MB heap and 16MB stack is an ok starting point.

8. Remove the helloworld.c file from the project and replace with repl-zynq/repl.c

9. build and run.