---
title: "mlab-vm-execution — Mova code model"
description: "Mova code model of mlab/src/vm.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/mlab/src/vm.rs.groupant/execution.groupant/"
---
Elamur: [Mova](https://md.mova.elamur.ai/free/en/) · [Dictionary](https://md.dictionary.elamur.ai/free/en/) · [Research](https://md.research.elamur.ai/free/en/) · **Groupants**

This page as HTML: <https://groupants.elamur.ai/free/en/mova/mlab/src/vm.rs.groupant/execution.groupant/>

# mlab-vm-execution

The groupant beside mlab/src/vm.rs in the Mova repository: what the code computes, what it never does, how to go back from its outputs, its invariants, cost and checks.

## Facts

- **kind:** groupant_fragment
- **status:** partial source bound model
- **source:** [`mlab/src/vm.rs`](https://github.com/ElamurAI/mova-free/blob/main/mlab/src/vm.rs)
- **source SHA-256:** `04ee871c37021946…`
- **covers:** Workspace transfer, pooled calls, arithmetic/index slow paths and dispatcher. (bytes 45698–88727)
- **part of:** [mlab-vm](https://md.groupants.elamur.ai/free/en/mova/mlab/src/vm.rs.groupant/)
- **repository folder:** [`mlab/src/vm.rs.groupant/execution.groupant`](https://github.com/ElamurAI/mova-free/tree/main/mlab/src/vm.rs.groupant/execution.groupant)
- **repository commit:** `855da7bd4a7b`

> **Implementation material.** A Mova code model describes this code at one source revision: partial models, finite checks and their stated scope. It is not a reviewed general exposition, and its labels are shown as written, never raised.

## Components

| component | label | where |
|---|---|---|
| **approximant** | partial | [approximant](#approximant) |
| **ast** | partial | `../syntax.json` |
| **cost** | symbolic source derived | [invariant](#invariant) |
| **descriptant** | present | [descriptant](#descriptant) |
| **invariant** | partial | [invariant](#invariant) |
| **tests** | executed bounded checks | [tests](#tests) |

## Obernants

The typed relations around the forward model: the behaviour complement (what the code never does), the reverse reconstruction (every input compatible with an output) and specialised views.

| id | type | label | where |
|---|---|---|---|
| `behavior_complement` | behavior_complement | partial source derived model | [behavior_complement](#behavior-complement) |
| `reverse_reconstruction` | reverse_reconstruction | partial source derived model | [reverse_reconstruction](#reverse-reconstruction) |
| `error_restore` | error_restore | partial source derived model | [error_restore](#error-restore) |
| `copy_on_write` | copy_on_write | partial source derived model | [copy_on_write](#copy-on-write) |
| `fallback_flow` | fallback_flow | partial source derived model | [fallback_flow](#fallback-flow) |
| `fault_scope` | fault_scope | partial source derived model | [fault_scope](#fault-scope) |

## Model text


### descriptant

#### mlab-vm-execution

Workspace transfer, pooled calls, arithmetic/index slow paths and dispatcher.

##### Epoch 2026-10-31

Half-open source bytes [45698,88727); bound by parent source hash and scoped byte hash. Model covers only this fragment; parent composition explains joins.

### approximant

#### Scoped forward relation

Import current frame to U/F/L/V registers; execute code; synchronize tree fallbacks and dyn calls; export all script variables even after returned error.

##### Domain and gap

Source-generated states within resource limits. Categorical relation has no executable percent surrogate.

### invariant

#### Scoped invariant

exec truncates end_stack on Err; finish_call restores frame/depth and clears pooled buffers.

##### Cost

Executed instructions plus delegated kernels, sync-list size, matrix COW and pooled frames. Loops unbounded; arithmetic uses f64 exceptional values and indices use dimension products.

### models

## Scoped typed relations

### behavior_complement

Out-of-bounds or nonintegral matrix coordinates exclude fast indexed write; shared Rc aliases exclude mutating the other alias. A fallback error excludes continuing dispatch but not its already synchronized writes.

### reverse_reconstruction

Final workspace does not reveal instruction count, prior overwritten registers or COW ownership. Stats constrain counts but not execution trace.

### error_restore

exec truncates end_stack on Err; finish_call restores frame/depth and clears pooled buffers.

### copy_on_write

asg_fast validates in-bounds double matrix then Rc::make_mut writes one cell.

### fallback_flow

Break/continue use patched fallback targets; Return ends execution; errors propagate after sync_in.

### fault_scope

vm:add affects nonconstant binary scalar AddBug, not every addition fast path.


### tests

#### Evidence scope

Parent selected tests: wave30_bounded_state_and_fallback, wave30_parse_runtime_and_output_state, wave30_synthetic_gate_fail_fast, vm_workspace_is_visible_after_run. This fragment shares parent syntax and finite checks; no separate test count or complete fragment coverage claim. Assertion-control association and unexecuted paths are in parent tests.md and source-test-map.json.