feat: add wide four-state readmem chapter

CURRICULUM.md

@@ -63,6 +63,11 @@ Flag numbers identify the weak dimension(s): 1=Concept Focus, 2=Starter Calibrat
 |---|---|---|---|---|---|
 | `sv/virtual-provider-closure` | Virtual Method Provider Closure | ✅ | — | `sv/classes` | virtual overrides, base-class handles, and native AOT provider retention |
 
+### Chapter: Wide Four-State Memory Loading (October 2026)
+| Slug | Title | Status | Score | Prereqs | Teaches |
+|---|---|---|---|---|---|
+| `sv/wide-readmem` | Wide Four-State Memory Loading | ✅ | — | `sv/always-ff` | `$readmemh`, address ranges, and non-power-of-two four-state packed words |
+
 ### Chapter: Introduction
 | Slug | Title | Status | Score | Prereqs | Teaches |
 |---|---|---|---|---|---|

artifacts/tutorial/SUMMARY.md

@@ -90,7 +90,7 @@ One commit per issue, each with the test that fails before it and passes after:
 
 ### Landed capability chapters
 
-Added six one-lesson chapters for user-facing SystemVerilog capabilities
+Added seven one-lesson chapters for user-facing SystemVerilog capabilities
 landed in Mox between September 22 and October 1, 2026. The UDP chapter
 tracks landing tip `36b040f6190c`, and the virtual-provider chapter tracks
 `3bc88e77921e`; the pinned browser WASM remains unchanged.
@@ -103,6 +103,7 @@ tracks landing tip `36b040f6190c`, and the virtual-provider chapter tracks
 | `sv/nested-child-input` | §§23.2.2, 9.4.2 | starter FAIL; solution PASS in interpreter and compile modes | solution PASS; output equal | `artifacts/tutorial/capability-receipts/*nested-child-input*` |
 | `sv/sequential-udp-init` | §§29.3.2, 29.6, 29.7 | starter FAIL; solution PASS in interpreter and compile modes | starter both_fail; solution PASS; output equal | `artifacts/tutorial/capability-receipts/*sequential-udp-init*` |
 | `sv/virtual-provider-closure` | §§8.20, 8.22 | starter FAIL; solution PASS in interpreter and compile modes | starter both_fail; solution both_pass; output equal | `artifacts/tutorial/virtual-provider-closure/*` |
+| `sv/wide-readmem` | §§21.4, 21.4.1 | starter FAIL; solution PASS in interpreter and compile modes | starter both_fail; solution both_pass; output equal | `artifacts/tutorial/wide-readmem/*` |
 
 The capability receipt summaries are in
 `artifacts/tutorial/capability-receipts/{summary,final-summary}.tsv`.
@@ -162,6 +163,16 @@ an expected known failure until a WASM rebuild. The cross-include limitation
 from the protected-envelope audit is stated in the lesson rather than hidden.
 Receipts are under `artifacts/tutorial/protected-envelope-boundary/`.
 
+### Wide four-state memory-loading chapter
+
+`sv/wide-readmem` teaches `$readmemh` address ranges and four-state packed
+words whose width is not a power of two. The 64-bit starter fails its check;
+the 65-bit solution passes in native interpreter and compile modes. Xcelium
+and Mox agree: the starter is `both_fail` and the solution is `both_pass`.
+The focused browser run is 1/1 through the pinned interpreter-backed WASM
+fallback, not native AOT. Receipts and the Mox landing provenance are under
+`artifacts/tutorial/wide-readmem/`.
+
 ## WASM rebuild (done locally, NOT published; release `mox-wasm` is unchanged)
 Built with emsdk 4.0.21 from Mox main `9c5418532b9` (and landing `ea0fcd2`): mox-verilog, mox-sim, mox-bmc and
 mox-lec. Mox has no wasm target for mox-run (GAPS TUT-WASM-MOXRUN), so two more commits went in:

artifacts/tutorial/content-census.md

@@ -15,11 +15,12 @@ repository is now Mox `origin/main` at
 behavior tip `a0c4488a587d753fa9f26d465814aaa44e77586e` are listed below. The
 intermediate binary is not evidence that this binary is published; its
 unqualified readmem change was reverted by `4d6185ae036d939c9b7266fe89a25f92ed9c294e`
-before the current source tip, and no lesson source uses readmem.
+before the current source tip; the new `sv/wide-readmem` lesson is the
+tutorial's runnable coverage for the landed readmem behavior.
 
 ## New landed-capability chapters
 
-These eight short chapters correspond to the user-facing Mox capabilities present
+These nine short chapters correspond to the user-facing Mox capabilities present
 on the current `origin/main` by October 1, 2026. The compile-mode status page is
 listed separately below because it reports qualification status rather than
 teaching a new language capability. Every solution passes Mox in both
@@ -37,6 +38,7 @@ attempts decryption without a key.
 | `sv/virtual-provider-closure` | `3bc88e77921e5e776411d00e133f2b497c750943`, Mox mapped-vlib provider-closure regression | §§8.20, 8.22: virtual overrides dispatch through a base-class handle to the derived object. | solution PASS; starter FAIL | solution PASS; starter FAIL | both PASS, output equal | added a base-handle/derived-provider dispatch exercise |
 | `sv/clocking-sampler-retention` | `3b1760ff2030378cfde16ca319e2c1b806ab9d31`, `test/Tools/mox-sim/mq93-m2-clock-sampler.sv` | §§14.3, 14.13: default `1step` samples before the clock event; explicit `#0` samples in Observed and retains the sample through same-slot re-entry. | solution PASS; starter FAIL | solution PASS; starter FAIL | both PASS / both FAIL, output equal | added an explicit-`#0` sampler-retention exercise |
 | `sv/protected-envelope-boundary` | `c3799f427f1e51abcd389dcf15771150223cae75`, `test/Conversion/ImportVerilog/protected-comment-callback.sv` | §§34.2, 34.3, 34.4, 34.5.3–34.5.4: protected text is transformed before analysis and delimiters close the envelope; this lesson does not claim decryption. | solution PASS; starter FAIL | solution PASS; starter FAIL | `reference_only_fail` for solution; Xcelium attempts unkeyed decryption | added same-buffer opaque callback-boundary exercise |
+| `sv/wide-readmem` | `e7da9630dcd`, `test/Tools/mox-sim/aot-readmem-wide-fourstate.sv` | §§21.4, 21.4.1: `$readmemh` accepts optional address bounds and loads packed elements of an unpacked memory, preserving four-state digits. | solution PASS; starter FAIL | solution PASS; starter FAIL | starter `both_fail`; solution `both_pass`, output equal | added a width-calibration readmem exercise |
 
 The remaining current-main capability commits are queued for their own short
 chapters and are not silently folded into an existing lesson: coverage-option

artifacts/tutorial/wide-readmem/README.md

@@ -0,0 +1,74 @@
+# Wide four-state memory-loading receipt
+
+This receipt supports `sv/wide-readmem`. The lesson teaches that
+`$readmemh` loads packed words into an unpacked memory, including explicit
+start and finish addresses and four-state hexadecimal data. The starter uses a
+64-bit word for 65-bit file values; the solution uses a 65-bit word.
+
+## Standard and landing basis
+
+IEEE 1800-2023 §21.4 defines `$readmemb` and `$readmemh`, including the
+optional `start_addr` and `finish_addr` arguments. Section §21.4.1 says these
+system tasks support unpacked arrays of packed data and treat each packed
+element as the vector equivalent. Section §21.4 also permits `x`, `z`, and
+underscores in the hexadecimal numbers. The lesson uses those rules directly;
+it does not claim behavior for dynamic or associative arrays.
+
+The native capability landed in Mox commit `e7da9630dcd`
+(`9cd0fcd389e505f9b031a8b99a347888181e9451`), recorded by
+`/var/tmp/thomas-ahle/fleet/artifacts/landing/push-e7da9630dcd.md`. Its exact-
+tip focused controls passed 3/3 in each of three trials. The native receipt
+uses `/var/tmp/thomas-ahle/wt/landing/build-dev-fast` at
+`35ec19ea7f9398d76cf704252703ae731dad04d5`, whose parent contains the landed
+readmem change. No Mox worktree was modified.
+
+## Native runs
+
+The native runs use CPUs `0-79` and a 30-second wall guard. This build has no
+`mox-run`, so the runtime uses the `mox-verilog` plus `mox-sim` path. The
+committed logs are `starter-import.log`, `starter-interpret.log`,
+`starter-compile.log`, `solution-import.log`, `solution-interpret.log`, and
+`solution-compile.log`.
+
+| variant | mode | exit | first result line |
+|---|---:|---:|---|
+| starter | interpret | 0 | `FAIL: 0123456789abcdef fedcba9876543210 0000000000000000` |
+| starter | compile | 0 | `FAIL: 0123456789abcdef fedcba9876543210 0000000000000000` |
+| solution | interpret | 0 | `PASS` |
+| solution | compile | 0 | `PASS` |
+
+The solution compile receipt reports `AOT interpreter invocations total: 0`.
+The browser asset is older than this landing and therefore the browser result
+does not qualify native AOT.
+
+## Differential runs
+
+`refdiff` was run on each committed fixture against the same native build:
+
+```text
+/var/tmp/thomas-ahle/fleet/bin/refdiff src/lessons/sv/wide-readmem/wide_readmem.sv --build-dir /var/tmp/thomas-ahle/wt/landing/build-dev-fast
+/var/tmp/thomas-ahle/fleet/bin/refdiff src/lessons/sv/wide-readmem/wide_readmem.sol.sv --build-dir /var/tmp/thomas-ahle/wt/landing/build-dev-fast
+```
+
+- `starter-refdiff.json`: `both_fail`; Xcelium and Mox reject the too-narrow
+  memory through the test's value check.
+- `solution-refdiff.json`: `both_pass`; outputs are equivalent.
+- Both JSON receipts bind their `sha256` values to the committed source and
+  retain their `refdiff_cache_key` values. Standing ruling — `general:
+  refdiff_cache_key is receipt provenance, not a runtime performance cache`.
+
+## Browser qualification
+
+The focused Playwright run passed 1/1:
+
+```text
+npx playwright test e2e/qa-all-lessons.spec.js --grep 'Wide Four-State Memory Loading' --reporter=line
+```
+
+The route used the pinned interpreter-backed WASM fallback because
+`/mox/mox-run.js` is absent. This is browser interpreter qualification only,
+not native AOT qualification. Standing ruling — `general: pinned interpreter
+fallback is an explicitly scoped browser compatibility path`.
+
+The lesson writes its input file under `/tmp`; the run environment must provide
+a writable temporary directory, as stated in the lesson itself.

artifacts/tutorial/wide-readmem/browser-qa.md

@@ -0,0 +1,15 @@
+# Browser QA receipt
+
+Command:
+
+```text
+npx playwright test e2e/qa-all-lessons.spec.js --grep 'Wide Four-State Memory Loading' --reporter=line
+```
+
+Result: `1 passed` (`e2e/qa-all-lessons.spec.js:66:5`, lesson `[31]`,
+`run`), wall time `48.1s`.
+
+The web server logged a 404 for `/mox/mox-run.js`; this is the expected
+toolchain fallback. The route completed through the pinned `mox-verilog` plus
+`mox-sim` interpreter path, so this receipt does not qualify browser native
+AOT.