CM2: Chimera Meta Machine

What is this?

This is a process virtual machine where execution is driven by tail calls, and function calls in bytecode correspond to Zig function calls. Locals are stored in a stack of registers and calls explicitly allocate the frame size,

The aim of this design (present in the wasm3 interpreter) is to use Zig suspend/resume to implement a limited form of algebraic effects (think resumable exceptions). Ultimately, CM2 will be a runtime for the Chimera programming language.

How do I run it?

Note that I only tested this on x86_64 Linux with Zig 0.10-dev.

Assuming you have a Zig toolchain up and running, I recommend you compile cm2 in fast release mode:

# gotta go fast
zig build-exe -O ReleaseFast cm2.zig -fstage1 --strip

The cm2 commandline program accepts a file.cm2 binary executable that's very hard to read and write. Instead, you can write CM2 programs in ASCII assembly and generate binary executables from them using the asm.py program.

You can start with the bench/fib.asm assembly program since it has comments explaining what each instruction does:

# outputs bench/fib.cm2
./asm.py bench/fib.asm
# fib(32) = 2178309
./cm2 bench/fib/cm2

There is no full documentation of the bytecode, outside of comments in cm2.zig, just yet.

Preliminary Benchmarks

The following was obtained on an x86_64 Linux system running an Intel(R) Core(TM) i5-6300U CPU @ 2.40GHz. You can see that CM2 is on par with wasm3, which is to be expected.

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
./cm2 bench/fib.cm2	185.2 ± 3.6	177.7	192.5	1.00
./wasm3-cosmopolitan.com --func fib bench/fib32.wasm 32	210.7 ± 1.5	208.7	214.0	1.14 ± 0.02
lua bench/fib.lua	347.4 ± 5.6	341.3	356.3	1.88 ± 0.05