{"id":17140950,"url":"https://github.com/biged/ioccc-6502","last_synced_at":"2025-07-25T16:33:02.082Z","repository":{"id":16102551,"uuid":"18847521","full_name":"BigEd/ioccc-6502","owner":"BigEd","description":"6502 and PET emulator from Stephen Sykes' IOCCC submission","archived":false,"fork":false,"pushed_at":"2024-04-27T19:20:43.000Z","size":552,"stargazers_count":4,"open_issues_count":1,"forks_count":2,"subscribers_count":3,"default_branch":"master","last_synced_at":"2024-10-15T20:23:48.440Z","etag":null,"topics":[],"latest_commit_sha":null,"homepage":null,"language":"C","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":"cc0-1.0","status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/BigEd.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":"LICENSE","code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null}},"created_at":"2014-04-16T16:42:56.000Z","updated_at":"2021-01-29T23:52:26.000Z","dependencies_parsed_at":"2022-07-15T23:30:34.266Z","dependency_job_id":null,"html_url":"https://github.com/BigEd/ioccc-6502","commit_stats":null,"previous_names":[],"tags_count":0,"template":false,"template_full_name":null,"repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/BigEd%2Fioccc-6502","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/BigEd%2Fioccc-6502/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/BigEd%2Fioccc-6502/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/BigEd%2Fioccc-6502/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/BigEd","download_url":"https://codeload.github.com/BigEd/ioccc-6502/tar.gz/refs/heads/master","host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":227598479,"owners_count":17791605,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2022-07-04T15:15:14.044Z","host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":[],"created_at":"2024-10-14T20:23:51.575Z","updated_at":"2024-12-01T16:47:18.927Z","avatar_url":"https://github.com/BigEd.png","language":"C","funding_links":[],"categories":[],"sub_categories":[],"readme":"ioccc-6502\n==========\n\n6502 and PET emulator from Stephen Sykes' IOCCC submission - see [the official site](http://www.ioccc.org/2005/sykes/) and [Stephen's blog entry](http://www.stephensykes.com/blog_perm.html?112)\n\nThe purpose here is to host a bug-fixed version of the emulator, and some efforts at deobfuscation.  See the [hint.text](hint.text) file for details of how to run it. (To run as a PET you will need a ROM image - instructions in the hint file.)\n\nThe original submission doesn't successfully run the in-ROM machine monitor, which alerted me to the possibility of bugs.  Other than the absence of decimal mode (which is a relatively common omission and a relatively harmless one) I found these:\n* BRK should be a 2-byte opcode\n* Bit 4 of the pushed status byte (P) must be zero when pushed by IRQ and otherwise one.\n\nTo find the bugs I ran [Klaus Dormann's test suite](https://github.com/Klaus2m5/6502_65C02_functional_tests). The emulator formerly failed and now passes (up to decimal mode.)\n\nHere's a screenshot of the code:\n![PET (shaped) emulator](screenshots/PET-source-code.png \"Source code shaped like a PET\")\n\n\nSee also the post on gplus by mos6502 [here](https://plus.google.com/108984290462000253857/posts/FHjRVUPxQQU).\n\nThe rules at the time for submissions to the International Obfuscated C Code Contest put winning entries into the public domain - so I've applied a CC0 license.\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fbiged%2Fioccc-6502","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fbiged%2Fioccc-6502","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fbiged%2Fioccc-6502/lists"}