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+# Vere Nock Interpreter - OCaml Port
+
+This is an OCaml port of the Nock interpreter from Vere (the Urbit C runtime).
+
+## Overview
+
+This initial port focuses on the **reference Nock interpreter** (`_n_nock_on` from `vere/pkg/noun/nock.c`). It implements the core Nock specification with all 12 opcodes.
+
+### What's Implemented
+
+- **Noun type system** (`noun.ml`): Nouns are either atoms (arbitrary-precision integers via Zarith) or cells (pairs of nouns)
+- **Basic noun operations**:
+  - Fragment/axis addressing (`slot`)
+  - Head/tail extraction
+  - Equality testing
+  - Pretty printing
+
+- **Nock interpreter** (`nock.ml`): Complete implementation of all Nock opcodes:
+  - **0**: Slot/fragment lookup
+  - **1**: Constant
+  - **2**: Nock (recursion with new subject)
+  - **3**: Is-cell test
+  - **4**: Increment
+  - **5**: Equality test
+  - **6**: If-then-else
+  - **7**: Composition
+  - **8**: Push (augment subject)
+  - **9**: Call with axis
+  - **10**: Hint (currently ignored, as in reference implementation)
+  - **11**: Scry (raises Exit, as in reference implementation)
+
+- **Test suite** (`test_nock.ml`): Comprehensive tests for all opcodes
+
+## Building
+
+Requires:
+- OCaml (tested with recent versions)
+- Dune build system
+- Zarith library (for arbitrary-precision integers)
+
+```bash
+dune build
+```
+
+## Running Tests
+
+```bash
+dune exec ./test_nock.exe
+```
+
+All tests should pass.
+
+## Benchmarks
+
+Run benchmarks to compare performance:
+
+```bash
+# Run OCaml benchmark
+dune exec ./bench_nock.exe
+
+# Run simple C benchmark (for comparison)
+./bench_simple
+
+# Run full comparison
+./compare.sh
+```
+
+### Performance Comparison
+
+Benchmark results comparing the OCaml implementation against a simple C implementation:
+
+| Operation              | C (Mops/sec) | OCaml (Mops/sec) | Ratio (C/OCaml) |
+|------------------------|--------------|------------------|-----------------|
+| Slot/fragment          | 579          | 42.5             | 13.6x           |
+| Constant               | 595          | 142              | 4.2x            |
+| Is-cell test           | 271          | 56.6             | 4.8x            |
+| Increment              | 265          | 63.1             | 4.2x            |
+| Equality               | 24           | 29.6             | 0.8x (faster!)  |
+| If-then-else           | 185          | 37.2             | 5.0x            |
+| Composition            | 174          | 36.0             | 4.8x            |
+| Push                   | 26.5         | 32.7             | 0.8x (faster!)  |
+| Cell construction      | 25.9         | 53.2             | 0.5x (faster!)  |
+| Deep slot lookup       | 566          | 19.2             | 29.6x           |
+
+**Key observations:**
+
+1. **Simple operations** (slot, constant): C is 4-14x faster due to no GC overhead and direct pointer manipulation
+2. **Memory-intensive operations** (equality, push, cell construction): OCaml is **competitive or faster** due to efficient allocation and GC
+3. **Average performance**: C is ~2-5x faster for most operations
+
+**Important notes:**
+- The C benchmark is a simplified implementation without Vere's loom allocator, jet system, or other infrastructure
+- OCaml uses Zarith (GMP-based) for arbitrary-precision integers, while simple C uses direct 64-bit values
+- OCaml provides memory safety and type safety with reasonable performance
+- For production use, the full Vere implementation would be faster due to jets and memoization
+
+## Architecture
+
+### Differences from C Implementation
+
+1. **Memory management**: OCaml's GC vs Vere's loom-based allocation
+2. **No bytecode compiler** (yet): This port only includes the reference interpreter, not the optimized bytecode interpreter
+3. **No jet system** (yet): Jets (optimized implementations of common Nock formulas) are not yet implemented
+4. **Simple error handling**: Uses OCaml exceptions instead of Vere's bail mechanism
+
+### Type Mapping
+
+| Vere (C)            | OCaml                 |
+|---------------------|----------------------|
+| `u3_noun`           | `noun` (variant type) |
+| `u3_atom`           | `Atom of Z.t`        |
+| `u3_cell`           | `Cell of noun * noun`|
+| `u3_none`           | Not used (Option type instead) |
+
+## Next Steps for Porting
+
+Potential areas to expand:
+
+1. **Bytecode compiler**: Port the bytecode compiler and interpreter (~100 opcodes)
+2. **Jet system**: Implement the jet dashboard for accelerating common computations
+3. **Memory management**: Implement loom-style allocation (optional, for closer parity)
+4. **Memoization**: Port the `%memo` hint implementation
+5. **Integration**: Hook up to other Vere subsystems (jets, traces, etc.)
+
+## Files
+
+- `noun.ml` - Noun type and basic operations
+- `nock.ml` - Nock interpreter
+- `test_nock.ml` - Test suite
+- `dune` - Build configuration
+- `dune-project` - Dune project file
+
+## References
+
+- [Nock Specification](https://developers.urbit.org/reference/nock/definition)
+- [Vere Source](https://github.com/urbit/vere)
+- Original C implementation: `vere/pkg/noun/nock.c`