chore(release): cut v2.5.0 "Rungwork" — the 6502 rung, and the two gates it cannot reach - #446
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contract it amends
Rung 2's interrupt-injection sweep has no oracle. The DUT half shipped in
v2.5.0 -- nmi_n/irq_n, the /NMI edge latch, level-sampled /IRQ, the
hijack decided at the push, delayed-I falling out of where the poll sits,
and testbench controls to assert either pin at a chosen cycle -- and none
of it can be compared against anything, because co-simulation needs the
same stimulus on both sides and `rustynes-core` has no way to receive it.
Searched rather than assumed: no injection entry point exists, and the
interrupts the oracle does produce come from hardware this rung does not
model -- /IRQ from the APU frame counter or a mapper, /NMI from the PPU.
## What the ADR decides, and what it costs
Four options are recorded with why each was rejected, because the
rejected ones are the argument. Doing nothing leaves the RTL's most
error-prone region resting on a reading of the documentation, in a
programme whose premise is that a reading of the documentation is not
evidence. Waiting for rungs 3 and 4 inverts the ladder: rung 3 would have
to be trusted before rung 2 could be checked, and a divergence would then
be ambiguous between the CPU and the PPU that produced the interrupt.
Comparing against a third emulator moves the problem somewhere harder.
So: a feature-gated, default-off injection API, under SIX constraints
that are the substance of the decision rather than a footnote. The two
that matter most are stated as preconditions of merging, not follow-ups:
* zero hot-path cost when off, asserted by MEASUREMENT;
* byte-identical default output verified with the feature ABSENT and
again PRESENT-BUT-UNUSED.
The second is a distinct case for a specific reason. `irq-timing-trace`
selects a DIFFERENT per-dot loop merely by being compiled in, and that
one reached the accuracy battery itself -- the exact failure this
constraint exists to prevent.
If either check fails the decision is VOID, not "revisit", and the
fallback is written down. A decision whose failure mode is undefined
tends to get argued into acceptance after the fact.
## The contract is amended where it is stated, in both places
ADR 0037's hard contract and the Fabric plan's both said "the emulation
core is untouched" and both now point at 0038. Amending one and leaving
the other is how the original claim survives its own revision -- and this
project has already published a false claim assembled from two true
statements nobody re-read together.
The honest restatement is "untouched in the default build, with one
default-off test feature", which is WEAKER than what eight releases of
notes have said, and the ADR says so under Consequences rather than
burying it: that claim's value came from being unqualified.
## What this does NOT reach
nestest 0-diff and the 5 M-cycle bus window stay blocked. Both need a
PPU and are rung 3. Nothing here closes them, and v2.5.0's notes continue
to say so.
No code changes in this commit. The API is not implemented here; this
records the decision to allow it and the conditions under which it may
land.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014qfTKi2M3swo7qnwvYCkDj
The review round on #445. Antigravity reported no blocking issues and one suggestion -- move the existing `assert_eq!(..., RAM_LEN)` above the new `ram_init` write so the length is validated before anything reaches disk. Correct, and sharper than reported: that assert covers the POST-RUN `ram` buffer, so `ram_init` had no length check at all. It is now checked, on itself, before the write. Why it matters more than an ordering nicety: a co-simulation testbench mirrors these 2 KiB through $1FFF, so a short buffer would place the bytes WRONGLY rather than fail -- surfacing as a bus divergence at an unrelated address, which is the most expensive way to learn about a length mismatch. ## CodeRabbit did not review this PR Rate-limited again -- one included review per hour, and the earlier `@coderabbitai review` on this PR returned the same Fair-Usage notice that v2.4.8's did. Recorded rather than left implicit: the ceremony on #445 covered TWO bots, not three, and Copilot's own attempt errored out. So the only substantive automated review this PR received is Antigravity's, and this commit is its one finding. Gates: fmt clean; clippy on the excluded crate 0 errors; the exporter builds. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_014qfTKi2M3swo7qnwvYCkDj
…ates
it cannot reach
Rungwork is the scaffolding you stand on to build the next thing, and the
honest name for this release: the rung it was scoped to close does not
fully close, for reasons that are structural rather than defects.
REAL: nine opcode-group ROMs at 2115 records; 4537 cycles of per-cycle
bus equality across all nine; 27,388 cycles of nestest at 8571
instructions; `pc` agreeing on 3551 of 3551 cycles and now a COMPARED
field. RTL is RustyNES_MiSTer@27171cd.
NOT: nestest 0-diff over the whole run, the 5 M-cycle window, and the
interrupt-injection sweep.
## Interrupts
nmi_n and irq_n with the distinction that matters -- /NMI EDGE-sensitive
and latching, /IRQ level-sampled. Implementing NMI as a level is the
classic error and is invisible on any test whose NMI stays asserted.
Delayed-I falls out of WHERE the poll sits rather than needing a special
case: it reads P before the retiring instruction changes it. The hijack
is decided at the push, not at entry -- deciding at entry makes it
impossible and nothing else changes, which is why it needs its own test.
Reset does not latch a pending NMI from an already-low line.
## Five defects, all found by the bus gate
RTS read the incremented address on its final cycle. AM_IZX's `default`
arm caught cycle 1, driving an effective address before the pointer byte
was read. AM_IZY tested `idx_page_cross` rather than `izy_cross` -- a
quantity with no meaning for a mode that adds Y to the FETCHED pointer --
and took five cycles where hardware takes six. AM_IZY also wrote at the
unfixed address when the index did not carry.
And `build()` stamped over every ROM's interrupt vectors, so opgroup8's
handlers were unreachable: BRK "worked" by falling through to the
program's first instruction, and BOTH SIDES WOULD HAVE AGREED, because
both read the same wrong ROM. The fill byte is NOP, not an impossible
value, so "was this written?" could not be answered by inspecting the
byte -- the assembler now returns the set of offsets the program wrote.
## The two gates that do not close
NESTEST STOPS AT A PERIPHERAL. It reads $2002 at cycle 27396. BOTH SIDES
ADDRESS $2002; only the data differs, because the oracle has a PPU and
this rung's testbench is flat memory. Rung 3 by design, and the 5 M-cycle
window hits the same wall sooner. The gate is bounded at 27396 and stated
as a number, because a gate whose extent moves silently is not a gate.
THE SWEEP HAS NO ORACLE. It needs NMI and IRQ asserted at chosen cycles
on BOTH sides, and rustynes-core exposes no injection API -- searched,
not assumed. So the pins, the hijack and delayed-I are IMPLEMENTED AND
NOT ORACLE-VERIFIED. BRK is verified, because a software interrupt needs
no pin and exercises the same seven-cycle sequence.
Saying this rather than shipping the number is the point. "The 6502 rung
closes" was this release's own scope, and a rung reported closed on a
gate it never ran is the exact failure this programme was built to catch.
## ADR 0038, and a contract amended in both places
A test-only, default-off injection API, six constraints, two of them
preconditions of merging: zero hot-path cost asserted by MEASUREMENT, and
byte-identical output verified with the feature ABSENT and again
PRESENT-BUT-UNUSED. That second case is distinct because `irq-timing-trace`
selects a different per-dot loop merely by being compiled in, and that one
reached the accuracy battery itself. If either fails the decision is VOID,
not "revisit", and the fallback is written down.
ADR 0037's hard contract and the Fabric plan both said "the emulation
core is untouched" and both now point at 0038. The honest restatement is
"untouched in the default build, with one default-off test feature" --
weaker than eight releases of notes have said, and recorded as a cost.
## No upstream sync
The cadence is amended: the next libretro/RetroArch sync waits for the
MiSTer core to be COMPLETE, at whatever vX.Y.0 that lands on. A lagging
display_version understates what shipped; a leading one overstates it.
## Gates
cargo fmt --all --check clean
cargo clippy --workspace --all-targets -D warnings 0 errors
cargo test --workspace 2233 passed, 0 suites failed
release audits (anchor/prose/notes/libretro) 8 / 8 / 2 / 3
The current-tag rule fired again, fourth consecutive release.
No crate under rustynes-{cpu,ppu,apu,mappers,core} changes, so
AccuracyCoin 141/141 (100.00%, RAM decoder) and nestest 0-diff hold BY
CONSTRUCTION.
Written from public documentation only. No reference NES core was opened;
none is present in the tree.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014qfTKi2M3swo7qnwvYCkDj
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This repository does not receive automatic reviews because it has fewer than 10 stars. ⚙️ Run configurationConfiguration used: Path: .coderabbit.yaml Review profile: ASSERTIVE Plan: Pro Plus Run ID: 📝 WalkthroughWalkthroughThe change promotes RustyNES to v2.5.0 “Rungwork”, records verification results and blocked gates, documents ADR 0038’s interrupt-injection contract, updates release metadata, and validates the exported RAM snapshot length. The emulation core remains unchanged. Changesv2.5.0 Release Update
Estimated code review effort: 2 (Simple) | ~10 minutes Merge Risk: 🟡 Moderate · up to This release changes published version, support, and validation claims, but the current head still leaves the zero-cost gate non-reproducible and contains conflicting accuracy and release-status documentation. Users and maintainers could receive incorrect verification or support information, so the PR is not merge-ready until these release contracts and records are reconciled. 🚥 Pre-merge checks | ✅ 9✅ Passed checks (9 passed)
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📝 Generate docstrings
🧪 Generate unit tests (beta)
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Antigravity review (Gemini via Ultra)This PR cuts the v2.5.0 "Rungwork" release by bumping workspace versions, updating the libretro Blocking issuesNone found. Suggestions
NitpicksNone. Automated first-pass review by Earlier review rounds (newest first)Round reviewed at 2026-08-23 05:48 UTCAntigravity review (Gemini via Ultra)This PR cuts the v2.5.0 "Rungwork" release, bumping versions across manifests, updating project documentation, and adding a validation check to the exported initial RAM buffer in the co-simulation testbench. Blocking issuesNone found. (The newly added Suggestions
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Actionable comments posted: 7
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Inline comments:
In `@CHANGELOG.md`:
- Around line 17-18: Reconcile the v2.5.0 identity between the CHANGELOG entry
and docs/release-notes/v2.5.0.md by renaming or updating the older release note
so it no longer describes a different release; preserve a single consistent
version, date, and release name before publishing.
In `@crates/rustynes-libretro/rustynes_libretro.info`:
- Line 8: Update the libretro metadata description’s mapper-family count to
match the authoritative release count of 172, keeping display_version at v2.5.0.
In `@docs/adr/0038-cosim-interrupt-injection-api.md`:
- Around line 89-92: Update the “Zero hot-path cost when off” section of the ADR
to define an executable benchmark gate: specify the exact full_frame A/B
command, benchmark runner, sample count, and maximum permitted delta, replacing
the subjective “within noise” criterion. Keep the gate as a precondition for
merging.
- Around line 94-100: Use one consistent bounded nestest validation contract
across the release documents: in docs/adr/0038-cosim-interrupt-injection-api.md
lines 94-100, require the absent/present-but-unused gate to use the bounded
comparison or explicitly defer full-run verification; in
docs/adr/0037-mister-fpga-core-independent-hdl-implementation.md lines 97-100,
replace the unqualified zero-diff claim with the bounded result and deferred
full-run gate; in to-dos/plans/v2.5.0-fabric-plan.md lines 16-19, align the hard
contract with Line 164’s unmet full-run status; and in
.github/release-notes/v2.5.0.md lines 57-58, remove the “by construction”
full-run claim and report only the bounded result.
Apply the same fix in `@CHANGELOG.md` around lines 63 - 64: Support documentation
must not promise unqualified full-run validation.
In `@docs/mister.md`:
- Around line 512-524: Update the obsolete status text in the documentation so
it no longer claims undocumented opcodes are undelivered or that rung 2 has not
begun. Remove that outdated block or clearly label it as historical, leaving the
newer nine-opcode-group and rung-2 evidence as the single authoritative current
status.
In `@SECURITY.md`:
- Line 5: Update the support matrix’s 2.4.x entry so 2.5.x is labeled as the
current line, while explicitly defining the support status for 2.4.x. Keep the
current-release references synchronized with the v2.5.0 declaration.
In `@to-dos/ROADMAP.md`:
- Line 62: Update the v2.5.0 “Rungwork” wording in the release-history sentence
to say “the current release” instead of “the current tag,” preserving the
surrounding version and AccuracyCoin details.
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.github/release-notes/v2.5.0.mdAGENTS.mdARCHITECTURE.mdCHANGELOG.mdCargo.tomlOVERVIEW.mdREADME.mdROADMAP.mdSECURITY.mdSUPPORT.mdVERSION-PLAN.mdcrates/rustynes-cosim/Cargo.tomlcrates/rustynes-cosim/src/bin/nes_golden_export.rscrates/rustynes-libretro/rustynes_libretro.infodocs/STATUS.mddocs/adr/0037-mister-fpga-core-independent-hdl-implementation.mddocs/adr/0038-cosim-interrupt-injection-api.mddocs/mister.mdto-dos/ROADMAP.mdto-dos/plans/v2.5.0-fabric-plan.md
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CodeRabbit reviewed this PR (rate limit permitting, which it did not on
the previous two) and raised seven. Four are real and fixed here; two are
checkably wrong and are refuted with the evidence rather than skipped.
## Applied
**"Within noise" is not a pass/fail criterion.** Correct, and it landed
while I was in the middle of failing to apply it: measuring ADR 0038's
precondition produced +1.3%, -1.4%, +1.7%, -1.0% across four workloads,
and I had no threshold to judge that against. Mixed signs are the
signature of code layout, not cost -- but "signature of" is not a gate.
Constraint 2 is now two checks, and the first is DECISIVE rather than
statistical:
2a cargo expand -p rustynes-core --lib | grep -c inject_ MUST be 0
2b full_frame vs a `main` worktree baseline, same runner,
one session, 100 samples, all four workloads within +/-1.0%
2a is a proof: the fields and branches are `#[cfg]`-gated, so a default
build emits none of them. **Measured on this implementation: 0.** 2b
corroborates. If 2a is 0 and 2b exceeds the band, the finding is the
measurement environment, because code that does not exist cannot cost
anything -- and saying so in advance stops that from becoming an argument
after the fact.
**Two "nestest 0-diff" claims mean different things.** Constraint 3's is
RustyNES's own, full-run, and true -- re-verified in both configurations
for this commit. The DUT's is bounded at cycle 27396 by its first $2002
read. The ADR now says which is which, and states that nothing in it
extends the bounded one. The reviewer took the wrong one, which is
evidence the wording invited it.
**docs/mister.md carried two incompatible current states.** A new status
section at the top and, ninety lines down, "the undocumented opcodes are
not delivered" and "rung 2 has not begun" -- both false since v2.4.9. The
older text is labelled historical rather than deleted, because the
reasoning still explains why the rung was scoped that way.
**SECURITY.md's matrix said 2.4.x was the current line** while its own
first line said v2.5.0. `bump_release.py` moves the prose anchor and not
the table. 2.5.x is now current and 2.4.x is Partial.
**Two files named v2.5.0 meant different releases.**
`docs/release-notes/v2.5.0.md` is the ENGINE-LINEAGE v2.5.0 (2026-06-11),
which shipped inside RustyNES v1.0.0; `.github/release-notes/v2.5.0.md`
is this release. Renaming the older one would destroy documented lineage,
so it gains a banner saying what it is. This is the exact confusion
AGENTS.md has a standing rule about, now visible at the file rather than
only in the rule.
## Refuted
**"Update the mapper description to 172."** It is **174**, and has been
since v2.3.4 added 176/2, 154 and 243. README states 174 in five places
and `AGENTS.md` agrees. `libretro_info_audit.rs` pins the file against the
workspace manifest, so a wrong count here would fail a gate. Not changed.
**"Replace 'current tag' with 'current release' -- no tag exists."** True
at PR time and true of every release cut in this project: `release-auto`
creates the tag when the version goes green on `main`, minutes after
merge. Refuted on #445 for the same reason and refuted the same way here,
because `release_state_prose_audit`'s fourth rule keys on that literal
phrase and is the gate that has caught this line drifting on four
consecutive releases. Rewording it would leave that rule matching zero
claims across the corpus -- policing nothing, silently.
Gates: release_anchor_audit / _state_prose / _notes_render all green;
markdownlint clean.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014qfTKi2M3swo7qnwvYCkDj
Owner
Author
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Antigravity's suggestion — considered and declined, with the reasoning. It proposes leaving That reads my reasoning correctly but applies it to the wrong file, and acting on it would undo a v2.3.5 fix. The "overstates" concern is about the file users see, which is not this one. RetroArch reads This local copy has a different job: it is the copy source. Letting it lag reintroduces exactly the decision the audit removed: at sync time someone has to work out what the value should be. That is the re-derivation step that went wrong before. So the local file stays pinned, and the thing that protects users is that no upstream PR is opened at all until the core is done. (Recording this rather than silently declining, since the suggestion engaged with the stated reasoning rather than restating a lint.) |
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Cuts v2.5.0 "Rungwork" — the 6502 rung, and the two gates it cannot reach.
Rungwork is the scaffolding you stand on to build the next thing, and the honest name here: the rung this release was scoped to close does not fully close, for reasons that are structural rather than defects.
Real: nine opcode-group ROMs at 2115 records; 4537 cycles of per-cycle bus equality across all nine; 27,388 cycles of nestest at 8571 instructions;
pcagreeing on 3551/3551 cycles and now a compared field. (RustyNES_MiSTer@27171cd)Not: nestest 0-diff over the whole run, the 5 M-cycle window, and the interrupt-injection sweep.
Interrupts
nmi_n/irq_nwith the distinction that matters — /NMI edge-sensitive and latching, /IRQ level-sampled. Delayed-Ifalls out of where the poll sits rather than a special case. The hijack is decided at the push, not at entry — deciding at entry makes it impossible and nothing else changes.Five defects, all found by the bus gate
RTSread the incremented address.AM_IZX'sdefaultarm caught cycle 1.AM_IZYtested the wrong page-cross signal, and wrote at the unfixed address. Andbuild()stamped over every ROM's interrupt vectors —BRK"worked" by falling through, and both sides would have agreed, because both read the same wrong ROM.The two gates that do not close
nestest stops at a peripheral. It reads
$2002at cycle 27396; both sides address it, only the data differs. Rung 3 by design. The gate is bounded at 27396 and stated as a number, because a gate whose extent moves silently is not a gate.The sweep has no oracle.
rustynes-coreexposes no injection API — searched, not assumed. So the pins, hijack and delayed-Iare implemented and not oracle-verified;BRKis verified, since a software interrupt needs no pin.Saying this rather than shipping the number is the point: a rung reported closed on a gate it never ran is the exact failure this programme was built to catch.
ADR 0038
A test-only, default-off injection API with six constraints — two of them preconditions of merging: zero hot-path cost by measurement, and byte-identity verified with the feature absent and present-but-unused. If either fails the decision is void, not "revisit". ADR 0037's contract and the Fabric plan both said "the emulation core is untouched" and both now point at 0038.
No upstream sync
Cadence amended: the next sync waits for the MiSTer core to be complete, not the next
vX.Y.0.Gates
fmtclean ·clippy --workspace --all-targets -D warnings0 errors · 2233 workspace tests, 0 suites failed · all four release audits green (8/8/2/3).No chip crate changes, so AccuracyCoin 141/141 and nestest 0-diff hold by construction.
Written from public documentation only. No reference NES core was opened; none is present in the tree.
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