Jotego just dropped the Gals Panic core for MiSTer and Analogue Pocket

Prolific FPGA developer Jose Tejada (better known as Jotego) has released the arcade core for Gals Panic on MiSTer, Analogue Pocket, and SiDi128.

Originally released in 1990 by Kaneko, Gals Panic took the territory-capture mechanics of Taito's 1981 classic Qix and brought them into the 16-bit era with an erotic twist. Players draw lines to claim portions of the screen and reveal a hidden background image while dodging enemies. It was a massive arcade success that spawned a long-running franchise. The Sega Saturn even received a port, which is also playable on the MiSTer.

Not all heroes wear capes. Jotego has been tackling some incredibly obscure hardware quirks lately, and his Patreon update this week is a perfect example of why his work matters. He announced the release on X, noting that the core is finally available to the public.

Three frame buffers for one game

The arcade hardware running Gals Panic is technically fascinating. Jotego notes that it uses two frame buffers to draw bitmaps and a third just for sprites. This is a highly unusual setup for arcade boards of that era, but it was likely the only sensible way the developers could let players draw arbitrary polygons on the screen.

The title screen's ribbon effect is even stranger. The game achieves the visual trick by disabling the frame buffer entirely and letting the sprite engine draw over the same dirty frame repeatedly. Because of these specific memory requirements, the core is limited to platforms with enough RAM, namely the MiSTer, Pocket, and SiDi128. You can find the core repository on his GitHub page.

An undocumented Konami instruction

The update also includes a major breakthrough for Konami arcade boards. Jotego was working on games like Aliens, Parodius, and Super Contra when he discovered an unknown instruction executing in Parodius. Ignoring it did not crash the game, but it caused missing lines in the score display because the custom Konami CPU was updating video memory during active video time.

He reported this finding to the MAME development team. They proposed a new instruction variant to handle it, which made total sense for the architecture. Jotego implemented the fix on the CPU core, and the visual glitches in Parodius vanished. Since this instruction appears in other places, players might notice subtle improvements across several classic Konami titles.

Audio fixes and a restored Sega racer

The rest of the patch notes read like a laundry list of welcome community fixes. The Toki and Cabal cores received more rework, completely fixing the audio problems in Cabal. A community member named Andrea Bogazzi discovered that the Rastan CPU was running 10 percent too fast, which is now corrected in the core.

Another contributor, Niknakniknak, fixed several incorrect parameters in the Yamaha OPL sound implementation. This audio fix impacts a massive list of games, including Karnov, Pang, Bubble Bobble, Haunted Castle, and various Gaelco titles.

Analogue Pocket users also get their OutRun core back. A bug introduced during Jotego's recent CPS3 development broke the Sega racer on the handheld, but it is fully restored now. Finally, Hyper Olimpic received some sound balance adjustments.

Jotego mentioned he plans to work on a few more small updates for a week or two before diving back into the massive CPS3 project. He noted that he needed a small break. Given the sheer volume of fixes shipped this week, he earned it.