René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"68000: Suggestion for additional DIVS/DIVU test cases","articleBody":"I believe there are currently no test cases for either DIVS or DIVU where the quotient is zero. If I modify my 68k DIVS and DIVU implementations to hardcode the Z flag to false, it still passes all of the DIVS and DIVU test cases.\r\n\r\nI noticed this because I had a silly bug in my implementation where I was setting the Z flag based on the final 32-bit value written back to the register, when as I understand it the correct behavior is to set the Z flag purely based on the 16-bit quotient.\r\n\r\nAs an example, here is a mostly hand-crafted test case for DIVU that failed in my implementation before the bugfix (minus the bus transactions which I don't currently have a way to generate easily):\r\n```\r\n{\r\n  \"name\": \"80c1 [DIVU D1, D0] xxxx\",\r\n  \"initial\": {\r\n    \"d0\": 1,\r\n    \"d1\": 5,\r\n    \"d2\": 0,\r\n    \"d3\": 0,\r\n    \"d4\": 0,\r\n    \"d5\": 0,\r\n    \"d6\": 0,\r\n    \"d7\": 0,\r\n    \"a0\": 0,\r\n    \"a1\": 0,\r\n    \"a2\": 0,\r\n    \"a3\": 0,\r\n    \"a4\": 0,\r\n    \"a5\": 0,\r\n    \"a6\": 0,\r\n    \"usp\": 2763053352,\r\n    \"ssp\": 2048,\r\n    \"sr\": 9985,\r\n    \"pc\": 3072,\r\n    \"prefetch\": [\r\n      32961,\r\n      40692\r\n    ],\r\n    \"ram\": [\r\n      [\r\n        3077,\r\n        228\r\n      ],\r\n      [\r\n        3076,\r\n        74\r\n      ]\r\n    ]\r\n  },\r\n  \"final\": {\r\n    \"d0\": 65536,\r\n    \"d1\": 5,\r\n    \"d2\": 0,\r\n    \"d3\": 0,\r\n    \"d4\": 0,\r\n    \"d5\": 0,\r\n    \"d6\": 0,\r\n    \"d7\": 0,\r\n    \"a0\": 0,\r\n    \"a1\": 0,\r\n    \"a2\": 0,\r\n    \"a3\": 0,\r\n    \"a4\": 0,\r\n    \"a5\": 0,\r\n    \"a6\": 0,\r\n    \"usp\": 2763053352,\r\n    \"ssp\": 2048,\r\n    \"sr\": 9988,\r\n    \"pc\": 3074,\r\n    \"prefetch\": [\r\n      40692,\r\n      19098\r\n    ],\r\n    \"ram\": [\r\n      [\r\n        3077,\r\n        228\r\n      ],\r\n      [\r\n        3076,\r\n        74\r\n      ]\r\n    ]\r\n  },\r\n  \"length\": 136,\r\n  \"transactions\": []\r\n}\r\n```","author":{"url":"https://github.com/jsgroth","@type":"Person","name":"jsgroth"},"datePublished":"2023-10-18T22:45:44.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/67/ProcessorTests/issues/67"}