Fix oversized D81 track initialization - #848
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D81 track counts are derived from file size. Values above the fixed 84-track arrays corrupt adjacent memory during layout initialization. Clamp at the shared boundary and cover 80-, 81-, 84-, and oversized layouts with a sanitizer host test. Closes GideonZ#846
Generate 80-, 81-, and 85-track fixtures, then verify physical track 81 through the emulated 1581 on real hardware.\n\nRefs GideonZ#846
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Summary
Root cause
D81 track counts come from image size. An image containing more than 84 tracks made
MfmDisk::init()index past its fixedside0andside1arrays, corrupting adjacent memory.The bound is enforced once in
MfmDisk::init(), covering every caller.Verification
make d81_tracks_testpasses under macOS Clang and Linux GCCThe E2E fixtures are generated during the test; no Wheels image is distributed.
Closes #846