We bring this week a small system that has been requested many times over the years. It is Gals Panic. This game follows the mechanics of QIX but it brings them to the 16-bit era. It is the starting point of a game series that continued onto home consoles. Indeed the SEGA Saturn has a version playable on the MiSTer FPGA.
This game is technically interesting too because it uses two frame buffers to draw the bitmaps and a third one to draw the sprites. This arrangement is very unusual for an arcade but it probably is the only sensible way of letting the player draw arbitrary polygons on the screen.
Even thinking of the sprite frame buffer itself, this game is still odd. The ribbon effect on the title screen is achived by disabling the frame buffer and letting the sprite engine draw over the same dirty frame over and over. Quite an unusual trick.
Because of the memory requirements of this system, the core is only available for MiSTer, Pocket and SiDi128.
Konami CPU New Findings
Aliens, Parodius, Super Contra... a lot of Konami games used a Konami-specific custom CPU. While working on these games I had found that there was an unknown instruction executed in Parodius, that didn't seem to break the game when ignored. The only odd thing was missing lines in the score because the CPU was updating the video memories during the active video time.
My report was picked up by the MAME team and they proposed a new instruction variant to apply for these cases, which made total sense. I implemented it on the CPU and the Parodius wrong lines went away. The instruction was used in other places too and maybe in other Konami games. So there might be some noticeable changes in Konami games in this release.
Other Updates
Toki/Cabal core has been reworked a bit more. The Cabal audio problems are fixed
The Rastan CPU was wrong by +10% in the core. Andrea Bogazzi found the issue and fixed it
A few parameters in Yamaha OPL were wrong. Niknakniknak contributed a fix for this. This might be noticeable in Toki, Cabal, Karnov, Gaelco games, Kunio-kun, Pang, Rastan, Bubble Bobble and House Castle
OutRun core for the Analogue Pocket has been restored, after a bug introduced while working on the CPS3 has been fixed
Sound for Hyper Olimpic has been adjusted for better balance
So that's all for this week. I may still work a bit more on other small things for a week or two before picking up again on CPS3. I needed a small break :-)