a28b830b38
Add a standard-library Python adapter and SHA-256/size lock for jsmolka/gba-tests ARM at a7113b67e63f83a9b321696ddd7042ccfad6c881. Retain sources and license locally, refuse tracked output paths or overwrites, verify offline inputs, and generate the source-verified eval/r12 suite checkpoint without patching the ROM. Add Python to the pinned Nix shell, offline adapter regressions, and public-test provenance/results documentation. Verified on Darwin arm64: Rust debug/release workspace tests, adapter tests, Clippy, rustdoc, native ROM and all demo window checks. The public test remains a failing baseline at instruction 0xe5b00004, PC 0x0800132c, in test 360.
98 lines
6 KiB
Markdown
98 lines
6 KiB
Markdown
# Pinned public ARM test
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The headless runner now executes the unmodified ARM ROM from [jsmolka/gba-tests](https://github.com/jsmolka/gba-tests).
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This is independent public test code, not a complete ARM7TDMI conformance suite or a new hardware measurement.
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The full public ARM test still fails. The first discovered CPU error is fixed; the next unsupported instruction is recorded below.
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## Prepare and run
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```sh
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direnv exec . python3 tools/prepare_gba_tests.py /tmp/gba-public-arm
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direnv exec . cargo run --locked --release -- --test-suite /tmp/gba-public-arm/suite.json > /tmp/gba-public-arm-report.json
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```
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The destination must not exist. Its parent directory must exist.
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Use a directory outside the repository or within the ignored `roms/` directory.
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The adapter downloads pinned files over HTTPS and checks each byte count and SHA-256 digest before creating output.
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It retains the upstream MIT license, README, ARM sources, shared assembly includes, and the original ROM.
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It also writes `suite.json` and `source-lock.json`. The manifest references the ROM relative to its own directory.
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No source rewriting, header removal, binary patching, or expected-result adjustment occurs.
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Python comes from the existing pinned Nix environment. No Python packages are required.
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The adapter bounds each download, sets a network timeout, and refuses existing output directories.
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A disk-write failure can leave partial output; choose a new destination for another attempt.
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Ordinary Rust and Python unit tests do not download or execute external ROMs.
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For an offline copy of the selected upstream files:
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```sh
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direnv exec . python3 tools/prepare_gba_tests.py /tmp/gba-public-arm-offline --source-dir /path/to/gba-tests
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```
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Offline input must match every selected file in the lock. A directory from a different revision can fail verification.
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The adapter does not overwrite or modify the input tree.
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## Provenance and checkpoint
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- Repository: `jsmolka/gba-tests`.
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- Revision: `a7113b67e63f83a9b321696ddd7042ccfad6c881`.
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- Upstream project license: MIT, copyright Julian Smolka. The license is retained with downloaded files.
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- ROM: `arm/arm.gba`, 8,824 bytes.
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- SHA-256: `77ee88662552bdc885c1080c0172ff119d54db791bd73b21808cf1ff1fe5b40e`.
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- All selected file hashes and sizes: [`tools/gba-tests-arm.lock.json`](../tools/gba-tests-arm.lock.json).
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This adapter uses the committed upstream binary, not a local rebuild.
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Upstream documents FASMARM as its assembler. No FASMARM build or source-to-binary reproduction was performed on Darwin.
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The binary's console header includes logo bytes. Do not copy the downloaded binary or header source into tracked files.
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Only original adapter code and provenance metadata are committed here.
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The ARM source initializes r12 to zero before testing.
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Each failure path sets r12 to its test number and branches to `eval`.
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Successful execution falls through to the same label with r12 still zero.
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At this pinned revision, `eval` is `0x08001d4c`, in ARM state.
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The ROM word there is the initial register save of the `m_vsync` macro.
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The source failure exits and their encoded branch targets were inspected against that address.
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The manifest stops before executing `eval` and requires `r12 == 0`.
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This avoids depending on the result renderer, VBlank polling, or BIOS division used to print failure numbers.
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It does not bypass the ROM's startup code or any CPU tests.
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In particular, evaluation must stop before using a possibly invalid stack left by a failed mode-switch test.
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The instruction at the checkpoint is checked during preparation, in addition to whole-file hash verification.
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The case budget is 1,000,000 successful machine steps, including our original BIOS boot.
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Timeouts, emulator diagnostics, and nonzero r12 all remain failures under the [normal suite rules](rom-tests.md).
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Preparation does not mean the test passed. The current run exits nonzero and writes a failed JSON report.
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## Observed results on Darwin arm64
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Before the compare/status fix:
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- The ROM reaches `eval` after 579 successful steps.
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- The assertion reports r12 = 234, in FIQ mode.
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- Running beyond `eval` produces an unmapped stack access because the CPU incorrectly remains in FIQ mode.
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- Upstream test 234 uses an ARM compare encoding with unused destination bits set to R15.
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The CPU previously treated that encoding as an ordinary compare and only changed arithmetic flags.
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It now restores CPSR from the current mode's SPSR when one exists, without writing a result to PC.
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User/System forms still use ordinary test/compare flags because those modes have no SPSR.
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Original regressions cover all four test/compare operations, exception banks, flags, masks, operands, timing, conditions, and invalid saved modes.
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See [CPU status behavior](hardware/cpu.md#processor-status-and-exceptions).
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After the fix:
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- Execution progresses past tests 234 and 235 and the PSR-transfer section.
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- After 861 successful steps, the runner reports unsupported instruction `0xe5b00004` at `0x0800132c`.
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- This is `LDR r0, [r0, #4]!` in upstream test 360, with base and destination equal.
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- The CPU is in System/ARM state, and r12 remains zero. The final completion checkpoint has not been reached.
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The load/writeback alias case is the next compatibility task. Do not weaken the assertion or label this run a pass.
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No public Thumb, timing, memory, BIOS, graphics, or unsafe suite has been claimed as passing.
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These results do not establish Pokémon Emerald compatibility.
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## References
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- [Pinned ARM entry and result flow](https://github.com/jsmolka/gba-tests/blob/a7113b67e63f83a9b321696ddd7042ccfad6c881/arm/arm.asm).
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- [Pinned test/result macros](https://github.com/jsmolka/gba-tests/blob/a7113b67e63f83a9b321696ddd7042ccfad6c881/lib/macros.inc).
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- [Tests 234 and 235](https://github.com/jsmolka/gba-tests/blob/a7113b67e63f83a9b321696ddd7042ccfad6c881/arm/data_processing.asm).
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- [Load/writeback alias tests](https://github.com/jsmolka/gba-tests/blob/a7113b67e63f83a9b321696ddd7042ccfad6c881/arm/single_transfer.asm).
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- [Pinned license](https://github.com/jsmolka/gba-tests/blob/a7113b67e63f83a9b321696ddd7042ccfad6c881/LICENSE).
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