Elamur Groupantsmlab-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
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 |
| ast | partial | ../syntax.json |
| cost | symbolic source derived | invariant |
| descriptant | present | descriptant |
| invariant | partial | invariant |
| tests | executed bounded checks | 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 |
reverse_reconstruction | reverse_reconstruction | partial source derived model | reverse_reconstruction |
error_restore | error_restore | partial source derived model | error_restore |
copy_on_write | copy_on_write | partial source derived model | copy_on_write |
fallback_flow | fallback_flow | partial source derived model | fallback_flow |
fault_scope | fault_scope | partial source derived model | 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.
This page in Markdown → https://md.groupants.elamur.ai/free/en/mova/mlab/src/vm.rs.groupant/execution.groupant/