> caius and Osso got West Story, a bootleg of Blood Bros.
Blood Bros. was one of my childhood favorites. Yay for new dumps! Thanks all!
Edit: Wow, West Story seems to be running slower than what it should be. Does the PCB have inadequate hardware, or was that just a result of the hackers messing with the code?
> Edit: Wow, West Story seems to be running slower than what it should be. Does the PCB > have inadequate hardware, or was that just a result of the hackers messing with the > code?
The bootleg hardware is indeed less powerful. The original Seibu hardware apparently used DMA to buffer the video RAMs (as all later Seibu games do). The bootleggers didn't implement that and instead hacked up the 68000 code to laboriously copy out the video memory in software.
> > Edit: Wow, West Story seems to be running slower than what it should be. Does the > PCB > > have inadequate hardware, or was that just a result of the hackers messing with the > > code? > > The bootleg hardware is indeed less powerful. The original Seibu hardware apparently > used DMA to buffer the video RAMs (as all later Seibu games do). The bootleggers > didn't implement that and instead hacked up the 68000 code to laboriously copy out > the video memory in software.
That's crazy. Will MAME be able to reproduce this behavior correctly?
> > > Edit: Wow, West Story seems to be running slower than what it should be. Does the > > PCB > > > have inadequate hardware, or was that just a result of the hackers messing with > the > > > code? > > > > The bootleg hardware is indeed less powerful. The original Seibu hardware > apparently > > used DMA to buffer the video RAMs (as all later Seibu games do). The bootleggers > > didn't implement that and instead hacked up the 68000 code to laboriously copy out > > the video memory in software. > > That's crazy. Will MAME be able to reproduce this behavior correctly?
It's not really complex, except for the possible waitstates / delay the DMA might cause periodically if you want to be 100% spot on with the timing.
A lot of other bootlegs have a 2nd copy of sprite ram and code to transform sprite lists from one format to another too, obviously this takes CPU cycles to do. Then you have bootlegs of bootlegs which do that, but where it's been confirmed on the PCB that the 2nd copy of spriteram isn't even the one that gets used (and infact, the ram doesn't exist, the code copies to nowhere)
> > > > Edit: Wow, West Story seems to be running slower than what it should be. Does > the > > > PCB > > > > have inadequate hardware, or was that just a result of the hackers messing with > > the > > > > code? > > > > > > The bootleg hardware is indeed less powerful. The original Seibu hardware > > apparently > > > used DMA to buffer the video RAMs (as all later Seibu games do). The bootleggers > > > didn't implement that and instead hacked up the 68000 code to laboriously copy > out > > > the video memory in software. > > > > That's crazy. Will MAME be able to reproduce this behavior correctly? > > It's not really complex, except for the possible waitstates / delay the DMA might > cause periodically if you want to be 100% spot on with the timing. > > A lot of other bootlegs have a 2nd copy of sprite ram and code to transform sprite > lists from one format to another too, obviously this takes CPU cycles to do. Then you > have bootlegs of bootlegs which do that, but where it's been confirmed on the PCB > that the 2nd copy of spriteram isn't even the one that gets used (and infact, the ram > doesn't exist, the code copies to nowhere) > > All good fun
I didn't mean because it was complicated; I meant because of the different hardware and how MAME's implementations can sometimes run better than the actual machine. Basically, "Will you be able to make sure MAME runs the game as crappily as the actual hardware does."
The commit to the source has just been made. Turns out the 2 "bad" roms mentioned in the source are actually the same on this PCB, so they didn't change.
However caius did measurements from the PCB so the bootlegs are going to sound radically different in terms of speed then before. But again this is using actual measurements from the PCB plugged into the driver.
As mentioned, Bill's Blood Bros. is the US Fabtek license so it's good to have that finally dumped!
> The commit to the source has just been made. Turns out the 2 "bad" roms mentioned in > the source are actually the same on this PCB, so they didn't change. >
this surprises me greatly, there are obvious 'bad dump' type problems with the explosions etc.
if the PCB caius has exhibits the same problem it's possible it's been repaired with bad roms at some point, this is always a possibility.
if it doesn't, then it could be some encryption, but last time I looked I concluded it was more likely they were bad roms.
> > The commit to the source has just been made. Turns out the 2 "bad" roms mentioned > in > > the source are actually the same on this PCB, so they didn't change. > > > > this surprises me greatly, there are obvious 'bad dump' type problems with the > explosions etc. > > if the PCB caius has exhibits the same problem it's possible it's been repaired with > bad roms at some point, this is always a possibility. > > if it doesn't, then it could be some encryption, but last time I looked I concluded > it was more likely they were bad roms.
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