FLUX Cross-Implementation Showcase

Demonstrates that the Python, Rust, and JavaScript FLUX VMs produce identical register state when running the same program.

Quick Start

# Run on Python VM only
python3 showcase/compile_and_run.py

# Run on all available VMs and compare
./showcase/run_all.sh

What It Does

1. Assembles tests/cross_impl.flx → 99 bytes of FLUX bytecode
2. Fixes jump offsets (cross-assembler emits absolute addresses; VM expects relative)
3. Executes the bytecode on the Python VM
4. Outputs the register state and an MD5 hash of R0–R15
5. Compares with expected values from the bytecode spec

Expected Register State

Register	Value	Source
R0	13	((10 + 5) * 2 - 4) / 2
R1	100	Signature constant
R2	15	Stack push/pop
R3	5	Signature constant
R4	5040	factorial(7)
R5	42	CMP operand
R6	42	CMP operand
R7	14	MOV + IADD test

Cross-Implementation Verification

When all three VMs are installed, run_all.sh produces:

  Python:     0e77c903e2b4c44c637cbcd670b8768b
  Rust:       0e77c903e2b4c44c637cbcd670b8768b
  JS:         0e77c903e2b4c44c637cbcd670b8768b

All hashes should match, confirming byte-identical execution semantics.

Files

• compile_and_run.py — Python VM runner with bytecode fixup
• run_all.sh — Multi-VM comparison script

See Also

• FLUX Bytecode Spec
• cross_impl.flx — The test program
• deadband.flx — Thermostat controller example