{"abstract":"The negative-zero marker tests the complete signed code for zero.","category":"PCM sample encoding","checks":8,"contract":"Decode sign-magnitude PCM with configurable physical sign-bit polarity and preserve numerical negative zero as a Boolean sideband.","contract_signature":"codes, width, invert_sign","evaluation_group":"s3-pcm-sign-magnitude-pcm","failed_approach":"Marking every numerical zero loses the distinction between signs.","family":"s3-pcm-sign-magnitude-pcm-zero-sideband","id":"FA-48956","implementations":{"attempt":{"sha256":"bad44ad8a74c484877f995b063cfff1d154b36f76330e7904d5d307f8168ec9b","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(codes, width, invert_sign):\n    mask=(1<<(width-1))-1\n    sign=1<<(width-1)\n    values=[]\n    zeros=[]\n    for code in codes:\n        magnitude=code&mask\n        negative=bool(code&sign)^invert_sign\n        values.append(-magnitude if negative else magnitude)\n        zeros.append(bool(magnitude==0))\n    return [values,zeros]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([0, 1, 7, 8, 9, 15], 4, False)), [[0, 1, 7, 0, -1, -7], [False, False, False, True, False, False]])\ncheck('oracle 2', solve(*([0, 8, 1, 9], 4, True)), [[0, 0, -1, 1], [True, False, False, False]])\ncheck('oracle 3', solve(*([], 4, False)), [[], []])\ncheck('oracle 4', solve(*([0, 3, 4, 7], 3, False)), [[0, 3, 0, -3], [False, False, True, False]])\ncheck('oracle 5', solve(*([0, 128, 255, 127], 8, False)), [[0, 0, -127, 127], [False, True, False, False]])\ncheck('oracle 6', solve(*([1, 2, 3], 4, True)), [[-1, -2, -3], [False, False, False]])\ncheck('oracle 7', solve(*([0, 4], 3, True)), [[0, 0], [True, False]])\nif N == 1: check('variant packet 1', solve(*[[0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15], 4, False]), [[0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7], [False, False, False, True, False, False, False, False, False, True, False, False]])\nif N == 2: check('variant packet 2', solve(*[[0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15], 4, False]), [[0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7], [False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False]])\nif N == 3: check('variant packet 3', solve(*[[0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15], 4, False]), [[0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7], [False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False]])\nif N == 4: check('variant packet 4', solve(*[[0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15], 4, False]), [[0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7], [False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False]])\nif N == 5: check('variant packet 5', solve(*[[0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15], 4, False]), [[0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7], [False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False]])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"45ad7f1b04410a9503c3f85072f5472aae7b72b39fdff46339980599ca24a906","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(codes, width, invert_sign):\n    mask=(1<<(width-1))-1\n    sign=1<<(width-1)\n    values=[]\n    zeros=[]\n    for code in codes:\n        magnitude=code&mask\n        negative=bool(code&sign)^invert_sign\n        values.append(-magnitude if negative else magnitude)\n        zeros.append(bool(negative and code==0))\n    return [values,zeros]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([0, 1, 7, 8, 9, 15], 4, False)), [[0, 1, 7, 0, -1, -7], [False, False, False, True, False, False]])\ncheck('oracle 2', solve(*([0, 8, 1, 9], 4, True)), [[0, 0, -1, 1], [True, False, False, False]])\ncheck('oracle 3', solve(*([], 4, False)), [[], []])\ncheck('oracle 4', solve(*([0, 3, 4, 7], 3, False)), [[0, 3, 0, -3], [False, False, True, False]])\ncheck('oracle 5', solve(*([0, 128, 255, 127], 8, False)), [[0, 0, -127, 127], [False, True, False, False]])\ncheck('oracle 6', solve(*([1, 2, 3], 4, True)), [[-1, -2, -3], [False, False, False]])\ncheck('oracle 7', solve(*([0, 4], 3, True)), [[0, 0], [True, False]])\nif N == 1: check('variant packet 1', solve(*[[0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15], 4, False]), [[0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7], [False, False, False, True, False, False, False, False, False, True, False, False]])\nif N == 2: check('variant packet 2', solve(*[[0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15], 4, False]), [[0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7], [False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False]])\nif N == 3: check('variant packet 3', solve(*[[0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15], 4, False]), [[0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7], [False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False]])\nif N == 4: check('variant packet 4', solve(*[[0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15], 4, False]), [[0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7], [False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False]])\nif N == 5: check('variant packet 5', solve(*[[0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15, 0, 1, 7, 8, 9, 15], 4, False]), [[0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7], [False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False]])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"Stipulated finite model; no claim of hardware timing or full file-format conformance. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"s3-pcm-sign-magnitude-pcm-zero-sideband","generated_at":"2026-09-29T14:44:55.571542+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Offline PCM interchange uses these exact bounded packet and sample representation decisions.","root_cause":"The negative-zero marker tests the complete signed code for zero.","sha256":"1909ca9d4a88c0b5a04de19caafa272b1358a0cd04305719451fc83651cb9e5e","title":"Sign magnitude pcm: zero sideband · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":38.758,"exit_code":1,"observations":[{"actual":[[0,1,7,0,-1,-7],[true,false,false,true,false,false]],"check":"oracle 1","expected":[[0,1,7,0,-1,-7],[false,false,false,true,false,false]],"passed":false},{"actual":[[0,0,-1,1],[true,true,false,false]],"check":"oracle 2","expected":[[0,0,-1,1],[true,false,false,false]],"passed":false},{"actual":[[],[]],"check":"oracle 3","expected":[[],[]],"passed":true},{"actual":[[0,3,0,-3],[true,false,true,false]],"check":"oracle 4","expected":[[0,3,0,-3],[false,false,true,false]],"passed":false},{"actual":[[0,0,-127,127],[true,true,false,false]],"check":"oracle 5","expected":[[0,0,-127,127],[false,true,false,false]],"passed":false},{"actual":[[-1,-2,-3],[false,false,false]],"check":"oracle 6","expected":[[-1,-2,-3],[false,false,false]],"passed":true},{"actual":[[0,0],[true,true]],"check":"oracle 7","expected":[[0,0],[true,false]],"passed":false},{"actual":[[0,1,7,0,-1,-7,0,1,7,0,-1,-7],[true,false,false,true,false,false,true,false,false,true,false,false]],"check":"variant packet 1","expected":[[0,1,7,0,-1,-7,0,1,7,0,-1,-7],[false,false,false,true,false,false,false,false,false,true,false,false]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[0, 1, 7, 0, -1, -7], [true, false, false, true, false, false]], \"expected\": [[0, 1, 7, 0, -1, -7], [false, false, false, true, false, false]], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [[0, 0, -1, 1], [true, true, false, false]], \"expected\": [[0, 0, -1, 1], [true, false, false, false]], \"passed\": false}, {\"check\": \"oracle 3\", \"actual\": [[], []], \"expected\": [[], []], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [[0, 3, 0, -3], [true, false, true, false]], \"expected\": [[0, 3, 0, -3], [false, false, true, false]], \"passed\": false}, {\"check\": \"oracle 5\", \"actual\": [[0, 0, -127, 127], [true, true, false, false]], \"expected\": [[0, 0, -127, 127], [false, true, false, false]], \"passed\": false}, {\"check\": \"oracle 6\", \"actual\": [[-1, -2, -3], [false, false, false]], \"expected\": [[-1, -2, -3], [false, false, false]], \"passed\": true}, {\"check\": \"oracle 7\", \"actual\": [[0, 0], [true, true]], \"expected\": [[0, 0], [true, false]], \"passed\": false}, {\"check\": \"variant packet 1\", \"actual\": [[0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7], [true, false, false, true, false, false, true, false, false, true, false, false]], \"expected\": [[0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7], [false, false, false, true, false, false, false, false, false, true, false, false]], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.041,"exit_code":1,"observations":[{"actual":[[0,1,7,0,-1,-7],[false,false,false,false,false,false]],"check":"oracle 1","expected":[[0,1,7,0,-1,-7],[false,false,false,true,false,false]],"passed":false},{"actual":[[0,0,-1,1],[true,false,false,false]],"check":"oracle 2","expected":[[0,0,-1,1],[true,false,false,false]],"passed":true},{"actual":[[],[]],"check":"oracle 3","expected":[[],[]],"passed":true},{"actual":[[0,3,0,-3],[false,false,false,false]],"check":"oracle 4","expected":[[0,3,0,-3],[false,false,true,false]],"passed":false},{"actual":[[0,0,-127,127],[false,false,false,false]],"check":"oracle 5","expected":[[0,0,-127,127],[false,true,false,false]],"passed":false},{"actual":[[-1,-2,-3],[false,false,false]],"check":"oracle 6","expected":[[-1,-2,-3],[false,false,false]],"passed":true},{"actual":[[0,0],[true,false]],"check":"oracle 7","expected":[[0,0],[true,false]],"passed":true},{"actual":[[0,1,7,0,-1,-7,0,1,7,0,-1,-7],[false,false,false,false,false,false,false,false,false,false,false,false]],"check":"variant packet 1","expected":[[0,1,7,0,-1,-7,0,1,7,0,-1,-7],[false,false,false,true,false,false,false,false,false,true,false,false]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[0, 1, 7, 0, -1, -7], [false, false, false, false, false, false]], \"expected\": [[0, 1, 7, 0, -1, -7], [false, false, false, true, false, false]], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [[0, 0, -1, 1], [true, false, false, false]], \"expected\": [[0, 0, -1, 1], [true, false, false, false]], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [[], []], \"expected\": [[], []], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [[0, 3, 0, -3], [false, false, false, false]], \"expected\": [[0, 3, 0, -3], [false, false, true, false]], \"passed\": false}, {\"check\": \"oracle 5\", \"actual\": [[0, 0, -127, 127], [false, false, false, false]], \"expected\": [[0, 0, -127, 127], [false, true, false, false]], \"passed\": false}, {\"check\": \"oracle 6\", \"actual\": [[-1, -2, -3], [false, false, false]], \"expected\": [[-1, -2, -3], [false, false, false]], \"passed\": true}, {\"check\": \"oracle 7\", \"actual\": [[0, 0], [true, false]], \"expected\": [[0, 0], [true, false]], \"passed\": true}, {\"check\": \"variant packet 1\", \"actual\": [[0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7], [false, false, false, false, false, false, false, false, false, false, false, false]], \"expected\": [[0, 1, 7, 0, -1, -7, 0, 1, 7, 0, -1, -7], [false, false, false, true, false, false, false, false, false, true, false, false]], \"passed\": false}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}