02106: ddragon2, ddragon2u: [possible] The game slows down in the first level, after the helicopter appears

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
02106	Speed	Major	Always	Aug 10, 2008, 08:53	Sep 15, 2013, 11:28

Tester	friol	View Status	Public	Platform	MAME (Official Binary)
Assigned To	Phil Bennett	Resolution	Fixed	OS
Status [?]	Resolved			Driver	technos/ddragon.cpp
Version	0.126u3	Fixed in Version	0.150	Build	Normal
		Fixed in Git Commit		Github Pull Request #

Summary	02106: ddragon2, ddragon2u: [possible] The game slows down in the first level, after the helicopter appears
Description	When the player moves into the first level, and the "parked" helicopter appears, the game slows down. The slow down seems to disappear when only zero or one enemies remain on the screen. The time counter on top also slows down.
Steps To Reproduce	Start the game, insert one coin, watch the "intro" sequence (the girl getting killed). Then fight the first two or three enemies, and scroll a bit on the right. When the "parked" helicopter appears, and two or three enemies come on the screen, the slowdown appears.
Additional Information	I've used default dip switch settings for this game.
Github Commit

Flags	Possible
Regression Version
Affected Sets / Systems	ddragon2, ddragon2u

Attached Files

No.02022 Haze Senior Tester Aug 10, 2008, 08:56	sounds correct.. double dragon (and the sequel) are well documented for having excessive slowdown...
No.02026 friol Tester Aug 10, 2008, 15:17	Don't know for double dragon, but I've played Double Dragon 2 on the real arcade, and I don't remember those slowdowns. If the game was such slow as it is in MAME, anyway, it would have been unplayable....
No.02029 Tafoid Administrator Aug 10, 2008, 16:17	I know first hand that memories related to arcade games can be a bit fuzzy at times. Until we can directly compare a PCB to this particular game, we cannot prove it's a bug. I've confirmed the observations of the slowdown but marked as possible (pending pcb verification). Hopefully someone who has access to a PCB will be able to document and record a gameplay session for comparison purposes.
No.06309 Tafoid Administrator Jun 27, 2010, 22:40 edited on: May 31, 2012, 04:34	Here is a youtube vid I came across. If you compare the introduction to that of MAME currently, you'll see there is little/no slowdown in the PCB presentation. Both fighting scenes are much slower in MAME. Approx 14 seconds for pcb vs. 18 for MAME for the first scene Approx 14 seconds for pcb vs. 25 for MAME at the mirror floor screen. There is something up.
No.06310 Haze Senior Tester Jun 27, 2010, 23:38	it appears that way, but some bootlegs had faster clocks, sadly, this video doesn't really prove much on it's own.
No.06311 Tafoid Administrator Jun 27, 2010, 23:46	Considering we don't even have any Double Dragon 2 bootlegs in MAME (granted the original DD was bootlegged to death) and the video matched behavior from and seemed to indicate the world version .. I took it as more likely original PCB than anything bootlegged. Perhaps someone in the know can contact the video poster and see if you can get some more verification that it's indeed an original game pcb.
No.07104 haynor666 Tester Jan 19, 2011, 10:58	The same situation is in first part and clones. Also slowdowns when more enemies appear and also slowdown of timer. Overclocking CPUs does not help here but speed up game when 1 or 0 enemies appear.
No.09776 Machone Tester Sep 6, 2013, 00:22 edited on: Sep 6, 2013, 00:23	Just a couple more reference videos to show the speed problem in MAME. The original game has less slowdowns.
No.09796 Phil Bennett Developer Sep 13, 2013, 22:39	Having cleaned up the sub CPU interrupt handling and common RAM access in accordance with the Double Dragon schematics, the slowdowns are now more infrequent.
No.09800 Machone Tester Sep 15, 2013, 10:53	Great work! Just compared the latest svn to the youtube vids and they sync up almost perfectly for Double Dragon II. In fact, in-game does seem to be perfect now. The only place where the original board differs slightly is when the game fades to black in the attract mode (at 3:55 in the last vid) - MAME fades out just a little too slowly, lags about half a second behind the pcb. Other than that it seems to be identical.
No.09801 Machone Tester Sep 15, 2013, 11:28	Similar story for Double Dragon. The only difference I could see is the part of the attract mode after the girl is carried away - the garage doors open too quickly in MAME for some reason. Before and after that I couldn't tell them apart, running them side-by-side.