docs(avm): redefine AVM as Lean-only ISA with adapter shims/backends

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Allaun Silverfox 2026-05-26 15:58:25 -05:00
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# Canonical Specification for the Adaptive Virtual Machine (AVM)
## State: CALIBRATED_PENDING_VALIDATION
This document is the canonical design for **AVM as a Lean-defined core ISA**.
## 1. AVM Instruction Set Architecture (ISA)
**Core rule:**
The AVM ISA defines a language-agnostic instruction set that serves as the bridge between mathematical languages and Python execution. The ISA consists of:
> **Lean is the source of truth. AVM is a Lean-only ISA.**
### Core Instruction Set
```python
# Stack-based operations
PUSH(value: Any) # Push a value onto the stack
POP() # Pop the top value from the stack
APPLY(func: Any) # Apply a function to the top N arguments
JUMP(label: int) # Unconditional jump
JUMP_IF(condition: bool, label: int) # Conditional jump
CALL(method: str) # Call a Python method
IMPORT(module: str) # Import a Python module
RETURN() # Return from function
All non-Lean languages (Python, Rust, C/C++, Go, etc.) are **adapter shims** (a.k.a.
backends) that *strip / serialize / reinterpret* into AVM programs and execute
AVM semantics. They do not define new semantics.
# Data operations
STORE(name: str) # Store a value in the symbol table
LOAD(name: str) # Load a value from the symbol table
DUMP() # Dump execution state for debugging
---
# Control flow
BEGIN(label: int) # Mark a label
END() # End of function
```
## 0. Definitions
### Data Representation
- **Values**: All values are represented as Python-compatible objects or fixed-point atoms
- **Types**: Minimal type system (int, Q16_16, Q0_16, bool, list, dict, function)
- **Constants**: Predefined constants for math operations (π, e, etc.) expressed in Q16_16
### 0.1 AVM Core
The **AVM core** is the ISA + operational semantics defined in Lean.
### Execution Model
- Stack-based virtual machine
- Type-checking during execution
- Error handling via Python exceptions
- Symbol table for cross-language data sharing
- Finite opcode set (closed-world)
- Finite value type set (closed-world)
- Deterministic step/run semantics
- No open string matching in decisions
- No dynamic "Any" values in the ISA
## 2. Semantic Stripping Algorithm
### 0.2 Adapter shims (backends)
Adapter shims are **extraction/interop targets**, not sources of truth.
```python
def strip_semantics(source: Any, threshold: float = 0.5) -> Any:
"""
Strips language-specific semantics while preserving functionality
"""
if is_invariant_root(source): # Check if already a fundamental structure
return source
They may:
- Encode/decode AVM programs and values (serialization)
- Interpret AVM programs (runtime interpreter)
- Emit target artifacts (Python bytecode, C, Rust, Verilog, FPGA netlists)
delta = calculate_delta(source) # 0-1 score of language dependency
if delta < threshold:
# Decompose into invariant components
components = decompose(source)
stripped_components = [strip_semantics(c, threshold) for c in components]
return reconstruct(stripped_components)
else:
# Preserve as invariant root
return source
They may **not**:
- Introduce new ISA meaning
- Add ad-hoc branching policy
- Decide invariants or costs outside Lean
def calculate_delta(node: Any) -> float:
"""
Computes language dependency score (0-1)
- 0: Pure invariant structure
- 1: Heavily language-specific
"""
# Implementation would analyze type signatures, syntax, etc.
pass
```
---
## 3. AVM Binary Interface (ABI)
## 1. AVM Instruction Set Architecture (ISA) — Lean-only
### Calling Convention
- **Stack layout**: CPython-compatible stack layout
- **Argument passing**: All arguments pushed in order
- **Return value**: Single value on stack
- **Error handling**: Python exceptions
The AVM ISA is a **Lean inductive** instruction set.
### Data Format
```python
class AVMValue:
def __init__(self, value: Any):
self.value = value
self.type = get_type(value)
### 1.1 Closed-world opcodes
The opcode set MUST be finite and enumerable.
def get_type(value: Any) -> str:
"""
Maps to CPython's internal type representation
"""
if isinstance(value, int): return "int"
if hasattr(value, 'is_q16_16'): return "Q16_16"
if hasattr(value, 'is_q0_16'): return "Q0_16"
# ... other types
```
A minimal core (illustrative, not final):
### Registration Protocol
```python
def register_primitive(name: str, func: Callable):
"""
Registers a primitive function for direct AVM execution
"""
_registry[name] = func
- Stack ops: `push`, `pop`, `dup`, `swap`
- Locals: `load`, `store` (indexed by `Fin n`)
- Control flow: `jump`, `jumpIf`, `halt`
- Fixed-point arithmetic primitives: `addSat`, `subSat`, `mul`, etc.
_registry = {}
```
### 1.2 Strict typing
The ISA operates over a finite type universe:
## 4. Invariant Root Extraction Process
- `Q0_16` (default for dimensionless scalars)
- `Q16_16` (only when range/precision forces it)
- `Bool`
- (Optional later) `UInt8`, `UInt16`, `UInt32`, fixed-width words for IO/register surfaces
```python
def extract_invariants(source: Any) -> List[Any]:
"""
Recursively extracts fundamental mathematical structures
"""
if is_primitive(source): return [source]
if is_container(source):
children = []
for child in source.children:
children.extend(extract_invariants(child))
return children
raise ValueError(f"Unsupported type: {type(source)}")
```
**No Float in core.** Float may exist only at boundary conversion shims.
## 5. Formal Specification in Lean 4
### 1.3 No dynamic foreign calls in ISA
The ISA must not contain opcodes like `CALL("pythonMethod")` or `IMPORT("module")`.
namespace Semantics.AVM
If extensibility is needed, it must be via **finite enums** (e.g. `Prim : Type`)
with semantics defined in Lean:
inductive Value where
| int : Int → Value
| q16 : Q16_16 → Value
| q0 : Q0_16 → Value
| bool : Bool → Value
- `Prim` is finite
- `evalPrim : Prim -> ...` is defined in Lean
- backends implement `Prim` by matching the Lean semantics
instance : informational_bind State Value where
isLawful s := true
cost s := 0 -- Base transition cost
extract s := "AVM_STATE"
---
def compile (source : SourceLang) : Value :=
match source with
| `int n => Value.int n
| `fixed n => Value.q16 n
| `ratio n => Value.q0 n
| `bool b => Value.bool b
```
## 2. Execution model
This specification provides a foundation for proving equivalence between source language semantics and AVM execution. The full implementation would include:
### 2.1 Step semantics
AVM execution is defined by a Lean function:
1. Type soundness proof
2. Preservation theorem
3. Progress theorem
4. Adequacy proof
- `step : Program -> State -> Outcome State`
## 6. CALIBRATED State Requirements
The AVM is considered **CALIBRATED** once the following conditions are met:
### 2.2 Run semantics (fuel)
AVM execution must have a fuel-bounded run function:
1. **Float Elimination**: All core primitive float references have been removed from the AVM ISA and Lean core.
2. **Type Definition**: `Q0_16` and `Q16_16` are explicitly defined and used as the primary numeric types.
3. **Behavioral Declaration**: Arithmetic, rounding (floor), and overflow (saturating) behaviors are formally declared and implemented.
4. **Boundary Conversion**: Explicit paths for converting external numeric formats (Int, Float-input) into `Q16_16` are defined.
5. **Determinism Invariant**: The AVM must achieve bit-exact reproducibility across all execution environments (Lean, Python-AVM, FPGA).
6. **Bind Semantics**: Composition of AVM instructions must follow the `informational_bind` metric laws.
7. **Validator Enforcement**: A pre-commit validator rejects any `f32`, `f64`, or `double` references in the `Semantics/AVM/` path.
- `run : Fuel -> Program -> State -> Outcome State`
## 7. Determinism Invariant
The AVM state transition function $f(S, I) \rightarrow S'$ must satisfy:
$\forall env_1, env_2 \in \{Lean, Python, FPGA\}, f_{env_1}(S, I) = f_{env_2}(S, I)$
This ensures that "Formal Drift" is mathematically impossible.
This is required for totality and for extraction to bounded substrates.
## 8. Boundary Conversion
```python
def to_q16_16(val: Any) -> int:
if isinstance(val, int):
return val << 16
if isinstance(val, float):
# Explicit boundary clip and scale
clamped = max(-32768.0, min(32767.9999, val))
return int(clamped * 65536)
raise ValueError("Invalid Boundary Format")
```
### 2.3 Determinism invariant
The state transition must be deterministic:
For any two backend environments implementing the same AVM ISA,
- `run_backend1(program, state) == run_backend2(program, state)`
up to the same observable projection.
---
## 3. Serialization boundary (shim responsibility)
Adapters may represent AVM programs and values in JSON or binary form.
Rules:
- Serialization formats must be versioned.
- No semantic meaning may depend on string parsing.
- Decoders must reject unknown opcodes/types.
---
## 4. Receipt / provenance policy
Every adapter execution must be able to emit a receipt packet containing:
- AVM ISA version
- adapter version
- input program hash
- output state hash
- (optional) projection hash
This makes drift observable and auditable.
---
## 5. Relationship to prior "universal adapter" language
Earlier drafts described AVM as a universal adapter from many math languages.
**This spec supersedes that framing.** The correct architecture is:
- **Lean -> AVM ISA (Lean-defined) -> adapter shims/backends**
If other languages are supported as inputs, they must be compiled into AVM by a
shim that produces AVM programs; but the AVM ISA itself remains Lean-only.
---
## 6. Claim boundary
This document defines AVM as a Lean-only ISA and a backend adapter ecosystem.
It does not claim:
- that every backend already exists
- that all proofs are complete
- that the ISA opcodes are final
It does claim:
- strict typing + closed-world opcodes is mandatory
- all semantics live in Lean
- all non-Lean code is an adapter shim, not a semantic authority