Forums

Sega Master System / Mark III / Game Gear
SG-1000 / SC-3000 / SF-7000 / OMV
Home - Forums - Games - Scans - Maps - Cheats - Credits
Music - Videos - Development - Hacks - Translations - Homebrew

View topic - MSX2 to SMS conversions (not MSX to SG1000)

Reply to topic
Author Message
  • Joined: 01 Aug 2012
  • Posts: 294
  • Location: Porto, Portugal
Reply with quote
MSX2 to SMS conversions (not MSX to SG1000)
Post Posted: Sat Sep 05, 2020 9:54 am
so i'm trying to start another thread, focusing MSX2 to SMS conversions, and not MSX to SG1000

as mentioning in another thread, converting msx2 games to sms is almost totally remaking the game, and needing to analyze the z80 disassembling listing deeply, at least for locating where the graphics part is, and remaking that totally since sms uses mostly hardware tiles, and msx2 "screen 5" (mostly used on msx2 games) uses vdp dma-like commands for simulating that, which both are structured in a totally different way, not mentioning also how sprites are structured (sms sprites are 4bitdepth, and msx2 sprites are 1bitdepth with 1 color per line, and allowing boolean "or" colours when sprites are overlapped, as shown at https://www.msx.org/wiki/The_OR_Color )

here is a list of some games that we perhaps could try start converting: https://www.msx.org/forum/semi-msx-talk/megapolls-and-opinions/best-msx2-game-ev...
  View user's profile Send private message Visit poster's website
  • Joined: 17 Feb 2020
  • Posts: 219
  • Location: United States
Reply with quote
Post Posted: Sat Sep 05, 2020 2:29 pm
I'm guessing we should start off with SD Snatcher. It's Konami's famous game for the MSX.
  View user's profile Send private message
  • Joined: 01 Aug 2012
  • Posts: 294
  • Location: Porto, Portugal
Reply with quote
Post Posted: Sat Sep 05, 2020 9:43 pm
i don't know - SD Snatcher is a floppy game (using 3 floppies - 720kb*3=2.1mb) - not only the whole game code should be rearranged, or simulating a kind of disk-rom (no idea how is that done)

another thing is that most msx2 games uses screen-5 in 256x212 size mode (rare, or no games at all, uses screen-5 in 256x192 size mode), so, the whole game display might need to be rearranged (just like Quinpl, from Bit2, the hud might need to be reduced in half for keeping the whole game playfield size)

another special situation is that most msx2 games from Konami (like SD Snatcher) uses k051649 or k052539 sound chip (that one called "scc", which is a kind of ay-3-8910, with 5 channels, and having 32 bytes for "samples" in each or almost each channel, depending on which sound chip used) - these sound chips, besides arcade games from Konami, came in cartridges - in Konami's floppy-based games using such chips, they came with a cartridge having the sound chip only, so they could be used from other games (like homebrew, or patched games) or whatever code using them (i think there is a vgm player developed recently using them as well)

a game that would be great converted from msx2 to sms is Xevious Fardraut Saga - the japanese sms fm soundchip is exactly the same from the fm version of this game - the 212 vs 192 vertical size wouldn't be so felt from the vertical scroll used in the game, but i have no idea how the hud would appear (and saying the same about Undeadline, Ashguine 2, etc.) - about this, Famicle Parodic, Aleste Gaiden and Hinotori might be easier because they don't use hud at all

and some games might not need any conversion at all because both exist in sms and msx2 afaik! :D (like Chuka Taisen) - perhaps analyzing both might provide us some clues?

some games like Space Manbow (a kind of sequel from Thunder Cross, from arcade) might be one of the trickiest to be converted - it uses screen 5 in the hud part, and screen 4 in the game playfield, wirh a smooth scroll using an undocumented bug found in the 9938 display chip
  View user's profile Send private message Visit poster's website
  • Joined: 17 Feb 2020
  • Posts: 219
  • Location: United States
Reply with quote
Post Posted: Sun Sep 06, 2020 12:57 pm
nitrofurano wrote
i don't know - SD Snatcher is a floppy game (using 3 floppies - 720kb*3=2.1mb) - not only the whole game code should be rearranged, or simulating a kind of disk-rom (no idea how is that done)

another thing is that most msx2 games uses screen-5 in 256x212 size mode (rare, or no games at all, uses screen-5 in 256x192 size mode), so, the whole game display might need to be rearranged (just like Quinpl, from Bit2, the hud might need to be reduced in half for keeping the whole game playfield size)

another special situation is that most msx2 games from Konami (like SD Snatcher) uses k051649 or k052539 sound chip (that one called "scc", which is a kind of ay-3-8910, with 5 channels, and having 32 bytes for "samples" in each or almost each channel, depending on which sound chip used) - these sound chips, besides arcade games from Konami, came in cartridges - in Konami's floppy-based games using such chips, they came with a cartridge having the sound chip only, so they could be used from other games (like homebrew, or patched games) or whatever code using them (i think there is a vgm player developed recently using them as well)

a game that would be great converted from msx2 to sms is Xevious Fardraut Saga - the japanese sms fm soundchip is exactly the same from the fm version of this game - the 212 vs 192 vertical size wouldn't be so felt from the vertical scroll used in the game, but i have no idea how the hud would appear (and saying the same about Undeadline, Ashguine 2, etc.) - about this, Famicle Parodic, Aleste Gaiden and Hinotori might be easier because they don't use hud at all

and some games might not need any conversion at all because both exist in sms and msx2 afaik! :D (like Chuka Taisen) - perhaps analyzing both might provide us some clues?

some games like Space Manbow (a kind of sequel from Thunder Cross, from arcade) might be one of the trickiest to be converted - it uses screen 5 in the hud part, and screen 4 in the game playfield, wirh a smooth scroll using an undocumented bug found in the 9938 display chip


Xevious would be absolutely great, maybe we can do Pac-Mania, although it has the Mega-RAM inside the game. How about others like original Aleste or Quarth? I also wish there were an SCC adapter for the SMS. Zemina's Nemesis 2 conversion had godawful music except for the sound effects.
  View user's profile Send private message
  • Joined: 08 Apr 2011
  • Posts: 27
Reply with quote
Post Posted: Mon Sep 28, 2020 5:33 pm
Well I'm certainly interested. Have any MSX2 titles been ported to any system in the past? Obviously I'd vote for Vampire Killer though that's gotta be too complex for a first outing.
  View user's profile Send private message
  • Joined: 17 Feb 2020
  • Posts: 219
  • Location: United States
Reply with quote
Post Posted: Fri Oct 09, 2020 9:49 pm
I actually have something in curiosity. Why not do a MSX compatible ROM just like Super Boy 3 or Cyborg Z? You can still optimize some stuff if you want to.
https://www.smspower.org/Tags/MSXCompatibleROM?sid=021729b5accd35f6ad4a004332e92...
  View user's profile Send private message
  • Joined: 17 Feb 2020
  • Posts: 219
  • Location: United States
Reply with quote
Post Posted: Wed Oct 14, 2020 11:11 pm
nitrofurano wrote
so i'm trying to start another thread, focusing MSX2 to SMS conversions, and not MSX to SG1000

as mentioning in another thread, converting msx2 games to sms is almost totally remaking the game, and needing to analyze the z80 disassembling listing deeply, at least for locating where the graphics part is, and remaking that totally since sms uses mostly hardware tiles, and msx2 "screen 5" (mostly used on msx2 games) uses vdp dma-like commands for simulating that, which both are structured in a totally different way, not mentioning also how sprites are structured (sms sprites are 4bitdepth, and msx2 sprites are 1bitdepth with 1 color per line, and allowing boolean "or" colours when sprites are overlapped, as shown at https://www.msx.org/wiki/The_OR_Color )

here is a list of some games that we perhaps could try start converting: https://www.msx.org/forum/semi-msx-talk/megapolls-and-opinions/best-msx2-game-ev...

You know what would be easy to port? You should port the MSX2 version of Pac-Man Collection (Demo) onto the SMS / GG. It's the smallest MSX2 demo I've seen. Here's the archived link: http://web.archive.org/web/20131111005032/http://www.opcodegames.com/games/pacma...
  View user's profile Send private message
  • Joined: 17 Feb 2020
  • Posts: 219
  • Location: United States
Reply with quote
Post Posted: Wed Oct 21, 2020 9:20 pm
nitrofurano wrote
so i'm trying to start another thread, focusing MSX2 to SMS conversions, and not MSX to SG1000

as mentioning in another thread, converting msx2 games to sms is almost totally remaking the game, and needing to analyze the z80 disassembling listing deeply, at least for locating where the graphics part is, and remaking that totally since sms uses mostly hardware tiles, and msx2 "screen 5" (mostly used on msx2 games) uses vdp dma-like commands for simulating that, which both are structured in a totally different way, not mentioning also how sprites are structured (sms sprites are 4bitdepth, and msx2 sprites are 1bitdepth with 1 color per line, and allowing boolean "or" colours when sprites are overlapped, as shown at https://www.msx.org/wiki/The_OR_Color )

here is a list of some games that we perhaps could try start converting: https://www.msx.org/forum/semi-msx-talk/megapolls-and-opinions/best-msx2-game-ev...

Hey, you there? I've been checking the posts on this lately, but there's no reply.
  View user's profile Send private message
Reply to topic



Back to the top of this page

Back to SMS Power!