lsylvestre / PADL24

Hardware implementation of OCaml using a synchronous functional language

Sylvestre et al., PADL 24 paper

This artefact, presented in the paper, includes:

• a compiler for the Eclat language
• an implementation of the OCaml virtual machine (VM) in Eclat (ocaml-vm/);
• the benchmarks from the paper (benchs/), with also hardware-accelerated versions (e.g., benchs/gcd/README.md) and instructions to reproduce;
• Eclat examples (listings) from the paper, with execution traces (e.g. examples/sum.png) and instructions to reproduce;
• a folder target in which are generated:
  • a main component main.vhdl,
  • a testbench tb_main.vhdl (for simulation)
  • and an interface synth/intel/top.vhdl (for synthesis);

Eclat instantaneous primitives are defined in target/runtime.vhdl

The paper compares our VM implementation (the ocaml/vmfolder) with an other implementation of the OCaml VM, called OMicroB (https://github.com/stevenvar/OMicroB) and a port of OMicroB on FPGA (https://github.com/jserot/O2B)

---

The VM includes :

• a configuration file (ocaml-vm/bytecode.ecl) generated by our auxiliary ocaml-vm/gen_bytecode from the output of the OCaml bytecode compiler;
• value representation (ocaml-vm/vm/mlvalues.ecl);
• dynamic memory in a static array (ocaml-vm/vm/ram.ecl);
• a memory allocator with garbage collector Stop&Copy (ocaml-vm/vm/alloc.ecl);
• the primitives of the bytecode interpreter (ocaml-vm/vm/runtime.ecl);
• external primitives (ocaml-vm/vm/prims.ecl);
• a bytecode interpreter (ocaml-vm/vm/vm.ecl);
• some definitions for physical I/Os (ocaml-vm/vm/target-specific/intel-max10/IOs.ecl);
• a reactive program executing the VM internally (ocaml-vm/vm/target-specific/intel-max10/main.ecl).

Installation

To build from source, the pre-requisites are:

• opam
• ocaml 4.14.1
• menhir
• ocamlclean
• obytelib
• dune
• for simulation: ghdl and GTKWave
• for synthesis: Intel Quartus II 22.1 lite, on a Terasic DE10-lite board (having an Intel MAX 10 FPGA)

Quick example (in simulation mode)

$ make SRC=ocaml-vm/tests/fibo.ml
$ make simul NS=200000

...

pc:19|acc:55<int>|sp:1011|env:4000<ptr> 
pc:20|acc:89<int>|sp:1010|env:4000<ptr> 
pc:19|acc:89<int>|sp:1006|env:4000<ptr> 
pc:20|acc:144<int>|sp:1005|env:4000<ptr> 
pc:30|acc:144<int>|sp:1001|env:1<int> 
======> 144
pc:32|acc:1<int>|sp:1001|env:1<int> 
pc:34|acc:1<int>|sp:1000|env:1<int> 
STOP : cycle:16427 
pc:34|acc:1<int>|sp:1000|env:1<int> 
cycle:16428 
cycle:16429 
STOP : cycle:16430 
pc:34|acc:1<int>|sp:1000|env:1<int> 
^C
$

Synthesis (on DE-10 lite FPGA board)

$ make FLAGS=" -intel-max10" SRC=ocaml-vm/tests/blink.ml
$ cd <QUARTUS-PATH>/bin
$ quartus
 
  - Processing > Start Compilation

  - Tools > Programmer > Start

  If USB-Blaster is not found:
  $ killall jtagd
  $ jtagd
  $ jtagconfig