{"id":22624658,"url":"https://github.com/barrettotte/game-2600","last_synced_at":"2025-03-29T03:16:52.838Z","repository":{"id":114090475,"uuid":"232710445","full_name":"barrettotte/Game-2600","owner":"barrettotte","description":"A screw around project in 6502 assembly for the Atari 2600 (VCS)","archived":false,"fork":false,"pushed_at":"2020-06-04T01:21:27.000Z","size":76,"stargazers_count":1,"open_issues_count":0,"forks_count":0,"subscribers_count":3,"default_branch":"master","last_synced_at":"2025-02-03T13:13:20.231Z","etag":null,"topics":["assembly-6502","atari-2600"],"latest_commit_sha":null,"homepage":"","language":"Assembly","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":null,"status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/barrettotte.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,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null}},"created_at":"2020-01-09T03:05:44.000Z","updated_at":"2021-05-10T18:57:35.000Z","dependencies_parsed_at":"2023-06-12T13:45:31.301Z","dependency_job_id":null,"html_url":"https://github.com/barrettotte/Game-2600","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/barrettotte%2FGame-2600","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/barrettotte%2FGame-2600/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/barrettotte%2FGame-2600/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/barrettotte%2FGame-2600/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/barrettotte","download_url":"https://codeload.github.com/barrettotte/Game-2600/tar.gz/refs/heads/master","host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":246131335,"owners_count":20728303,"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":["assembly-6502","atari-2600"],"created_at":"2024-12-09T00:17:18.026Z","updated_at":"2025-03-29T03:16:52.799Z","avatar_url":"https://github.com/barrettotte.png","language":"Assembly","funding_links":[],"categories":[],"sub_categories":[],"readme":"# Game-2600\n\nSome fun messing around with 6502 assembly on the Atari 2600 (VCS).\n\n\n## Game\nThis isn't quite a game; its more of a screw around project I kicked around.\n\nAt this point its only a skeleton and has the following:\n* Scoreboard and timer BCD display\n* Player movement with joysticks\n* Graphics and color binary loading\n* Reset button\n* A bit of black and white TV support\n* Random numbers via Linear Feedback Shift Register (LFSR)\n\n\nI really wanted to do more with this. \nBut, truthfully I just don't feel like working on it anymore. \nIts time for this to go on the shelf.\n\n\n## Screenshot\nYeah...this is all I have after ~2 weeks of messing around. This stuff is difficult for me.\n![screenshot.png](screenshot.png)\n\n\n## Stella Emulator Controls\n* Arrow keys - joystick\n* Spacebar - fire\n* F2 - reset\n* F3 - color TV\n* F4 - black and white TV\n* PAUSE - pause emulator\n\n\n## Unimplemented Ideas\n* Full black and white TV support\n* Player and enemy projectiles\n* Basic pathfinding for Enemy\n* Difficulty switches increase enemy speed\n* Random generated playfield obstacles\n\n\n## Notes\n\n\n#### Memory Map\n```\n+---------------------------+\n|       TIA Registers       | $00-$7F\n+---------------------------+\n|         PIA RAM           | $80-$FF\n+---------------------------+\n|           ???             |\n+---------------------------+\n|    PIA Ports and Timer    | $280-$297\n+---------------------------+\n|           ???             |\n+---------------------------+\n|       Cartridge ROM       | $F000-$FFFF\n+---------------------------+\n```\n\n\u003cbr\u003e\n\n#### NTSC Video Frame\n```\n\n+-------------------------------------------------+        \u003c-----+\n|                 Vertical Sync                   |   3 lines    |\n|                                                 |              |\n+-------------------------------------------------+              |\n|                 Vertical Blank                  |  37 lines    |\n|                                                 |              |\n+--------------------+----------------------------+              +-- 262 lines\n|    Horiz.          |           Visible          |              |\n|    Blank           |            Frame           | 192 lines    |\n|                    |  \u003c-- 160 color clocks --\u003e  |              |\n+--------------------+----------------------------+              |\n|                    Overscan                     |  30 lines    |\n|                                                 |              |\n+-------------------------------------------------+        \u003c-----+\n\n|--------------  228 color clocks ----------------|\n|---------------  76  CPU cycles -----------------|\n\n```\n\n\n## References\n**Main reference**: https://atariage.com/forums/profile/3056-spiceware/ . This guy is absolutely incredible with 6502 asm.\n\n\n* 6502 instruction set with cycle counts - https://www.masswerk.at/6502/6502_instruction_set.html\n* Atari 2600 killer hacks - https://atariage.com/forums/topic/71120-6502-killer-hacks/page/3/?tab=comments#comment-1071314\n  * ```.byte $2C``` - \"skip 2 bytes\" pseudo-instruction (ABS BIT)\n* Counting cycles on Atari 2600 - https://www.randomterrain.com/atari-2600-memories-guide-to-cycle-counting.html\n* DASM Macro Assembler - https://github.com/munsie/dasm\n* Introduction to Atari2600 - https://www.randomterrain.com/\n* Sprite ASM Generator - https://alienbill.com/2600/playerpalnext.html\n* Stella Emulator - https://stella-emu.github.io/\n* Unofficial 6502 opcodes - https://wiki.nesdev.com/w/index.php/Programming_with_unofficial_opcodes\n  * ```dcp $0F``` - decrement at memory address and compare with accumulator\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fbarrettotte%2Fgame-2600","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fbarrettotte%2Fgame-2600","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fbarrettotte%2Fgame-2600/lists"}