it was just a data decompression chip on the snes alpha2 , nothing more.
capcom used a couple chips in megaman x too which they didn't use again, for transparency etc.
check the wikipedia entry
# DSP-1 chip: This fixed-point Digital Signal Processor chip was created to allow programmers to generate more enhanced Mode 7 rotation and scaling effects in their games, and to perform very fast vector-based calculations. The chip can be found most notably in Pilotwings and Super Mario Kart, as well as a few other games. Later revisions of the chip, the 1A and 1B, were functionally the same but included bugfixes in their internal math calculations.
# DSP-2 chip: A bitmap scaling and bitplane conversion chip used only in one game cartridge, Atari's port of Dungeon Master to the SNES console.
# DSP-3 chip: An assistant chip used only in one Japanese game for the Super Famicom titled SD Gundam GX. Although this chip does handle graphics decompression and bitplane conversion, a large portion of memory inside this chip is dedicated to rendering a very complicated title screen, leading one to the likely conclusion that its inclusion was more intended to prevent the game from being easily pirated.
# DSP-4 chip: A DSP used in only one game cartridge, Top Gear 3000. It primarily helped out with drawing the race track, especially during the times that the track branched into multiple paths, which was a unique feature of this type of game at the time.
# S-DD1 chip : Other than its normal processing and copy protection duties, this chip was primarily a memory compression chip. This allowed games to be bigger than normal by compressing the data. Games that used this chip were Street Fighter Alpha 2 and Star Ocean.
# C4 chip: A chip created by Capcom. This chip was used to handle the wireframe effects, perform more general trigonometric calculations, and to help out with sprite positioning and rotation. The chip was used in Mega Man X2 and Mega Man X3.
# SA-1 chip: This is an ASIC chipset with a 65c816 8/16-bit processor core, clocked at 10MHz, containing some extra circuitry specified by Nintendo, including some fast RAM, a memory mapper, DMA, several programmable timers, and the region lockout chip. The SA-1 was a multipurpose chip that allowed games such as Kirby Super Star, Kirby's Dream Land 3, and Super Mario RPG, as well as the Super Game Boy to stay competitive in the changing marketplace during the aging SNES/SFC's final years.