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NES (Games) Graphics Power Entertainment Games Technology

28 Years Later, Hacker Fixes Rampant Slowdown of SNES' Gradius III (arstechnica.com) 58

Ars Technica's Kyle Orland reports that Brazilian ROM hacker Vitor Vilela has released a ROM patch for the hit arcade game Gradius III, creating a new, slowdown-free version of the game for play on SNES emulators and standard hardware. "In magazine screenshots, the game's huge, colorful sprites were a sight to behold, comparable to the 1989 arcade original," writes Orland. "In action, though, any scene with more than a handful of enemies would slow to a nearly unplayable crawl on the underpowered SNES hardware." From the report: The key to Vilela's efforts is the SA-1 chip, an enhancement co-processor that was found in some late-era SNES cartridges like Super Mario RPG and Kirby Super Star. Besides sporting a faster clock speed than the standard SNES CPU (up to 10.74 Mhz versus 3.58 Mhz for the CPU), SA-1 also opens up faster mathematical functions, improved graphics manipulation, and parallel processing capabilities for SNES programmers.

The result, as is apparent in the comparison videos embedded here, is a version of Gradius III that Vilela says runs two to three times faster than the original. It also keeps its silky smooth frame rate no matter how many detailed, screen-filling sprites clutter the scene. That's even true in the game's notorious, bubble-filled Stage 2, which is transformed from a jittery slide show to an amazing showcase of the SNES' enhanced power. As if that wasn't enough, the patch even slashes the game's loading times, cutting a full 3.25 seconds from the notably slow startup animation.
Vilela notes that the lack of slowdown "makes it incredibly super difficult" and even suggests that "some arcade segments of the game do not look RTA (real-time action) viable with SA-1. But we shouldn't underestimate the human capabilities."
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28 Years Later, Hacker Fixes Rampant Slowdown of SNES' Gradius III

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  • by Anonymous Coward

    It's true that such a thing couldn't have been made by Konami at the time (they didn't have the external coprocessor), but it's still amazing regardless. It looks like someone burned it onto a ROM and ran it on hardware (hardware featuring the expansion processor too).

    The concern he has about the game being too hard now, I totally get- when that game got busy enough to really slow down, it got WILDLY busy.

  • by antdude ( 79039 ) on Saturday May 11, 2019 @03:12AM (#58573090) Homepage Journal

    Like the original Double Dragon's slow downs in all ports?

    • This is a custom chip for SNES carts, they'd have to make a different spec for each system and alter each game.

      At that point you might have more success and less of a wait with overclocking.

      https://nobitleftbehind.wordpr... [wordpress.com]

  • In magazine screenshots, the game's huge, colorful sprites were a sight to behold, comparable to the 1989 arcade original .... In action, though, any scene with more than a handful of enemies would slow to a nearly unplayable crawl on the underpowered SNES hardware.

    Then it was perfectly comparable, because the arcade also suffered from severe slowdown. Check it. [youtube.com]

  • pretending it was the original could it be considered "driving someone to suicide"?

  • Mostly I just remember when I was younger, I thought it was like a highlight for an awesome moment. Bullet Time before The Matrix made video games obsess over it for a while. Of course I was too young to realize that was just the system dying under pressure of sending so many enemies at me.... but it just felt cool. Hell, it still kind of does when you go back to the old games. I don't ever remember getting upset that the game slowed down during action.
  • So let me get this straight. Some SNES carts (10 in total, from what I found) had a processor chip (the SA-1, among others) that allowed for game quality beyond what the console itself could produce. The Gradius III cart did NOT have this chip, however the ROM code was patched as if it did have the chip. I presume emulators can trivially include SA-1 functionality if a flag is set in the ROM config, thus this is useful within emulators.

    However, if one could swap out the ROM code in an actual Gradius III

    • However, if one could swap out the ROM code in an actual Gradius III cart, this would not work, since it doesn't have the SA-1.

      Right, but you could put the ROM code in a cart which does have the SA-1, and put a Gradius III sticker on it.

    • SA-1: Not quite (Score:5, Informative)

      by DrYak ( 748999 ) on Saturday May 11, 2019 @03:49PM (#58575340) Homepage

      Some SNES carts (10 in total, from what I found) had a processor chip (the SA-1, among others) that allowed for game quality beyond what the console itself could produce.

      Huh, you're seriously underestimating how much widespread enhancement chips [wikipedia.org] were on the SNES. 10 is closer to the number of *different types of chips* available for SNES carts, with many dozens of carts using one of these.

      That's the dirty secret about SNES :
      probably half of the SNES games you played weren't *actually* *SNES* games, but SA-1 games, Super FX games, etc. that used the SNES as a glorified gamepad-prober + framebuffer and relied on extra chip to do the game.
      (Including popular stuff like Yohsi Island, Mario Kart, etc.)
      The most obvious example being the Super Game Boy (literally a gameboy inside a SNES cartridge), the most recent example being the "MD adapter" you can find on aliexpress and ebay (literally a Megadrive/Genesis on-a-chip, inside a SNES cartridge. But for cust-cutting reasons, it doesn't leverage the SNES video out but has its own video in a kind of Sega 32x-style)

      The practice isn't anything new.
      Back in the 8-bit era, most game had to rely on "memory mapper" [smspower.org] to have games larger than the tiny 64kb address space of 8bit CPUs (Z80 and 6502). (The exception being the PC Engine, as it had its own mapper built-in).
      Most consoles could also accept external audio source either in cartridge (I've heard Atari used that) or on an extension port. [segaretro.org] (*).
      And given how primitive the NES was (didn't even have raster interrupts), it had quite a few extra functionality packed into its mappers [nesdev.com]
      SNES being designed that much around the ability to use extra chips isn't that much surprising.
      (A few like the PC Engine and the SEGA GameGear could even accept external *Video* input. The SuperGrafx used it (it is literally a PC Engine with a second VDP that can mix its planes and sprites with the main one) and the GameGear Tunner relied on it (it is not DMA-ing the video image into the tile buffer, the tunner *litterally takes over* the display using the digital video input)

      BTW: I suspect that's why the first joint project of making a plain CD-ROM drive with Sony for the SNES did fail - you can't (easily) pack extra chips on a CD-ROM.

      BTW: it's also why SNES emulation is a bit more complicated, despite being a slower device than the MegaDrive - you need to support the plethora of extra chips, too.

      In the specific case of this Gradius III : the SA-1 is almost just a 3x faster 65C816 CPUs.
      The patch "solves" the Gradius III slow-down problems simply by running it 3x faster. Brilliant!

      I presume emulators can trivially include SA-1 functionality if a flag is set in the ROM config, thus this is useful within emulators.

      Most emulator support emulating SA-1, yes. It's indeed straight forward.

      However, if one could swap out the ROM code in an actual Gradius III cart, this would not work, since it doesn't have the SA-1.

      That is the point were it's a bit more complicated than that:
      the use of enhancement chip was *so much pervasive* on SNES, that most ROM-dumper/floppy-backup back then at least tried to do something about it.
      Some at least supported a built-in SA-1 (due to the large prevalence, see the first Wikipedia link. Probably because it's very similar to the native 65c816).
      Some even supported exchangeable "stem" (I don't how to call it, the bridge between the floppy drive/ram drive and the SNES cart slot) with alternative chips built-in, so other games than SA-1 could be supported. Yet others, according the Youtube reviews, used a piggy back cartridge to not only rely on its copy-protection chips (like your garden variety regio

      • by Agripa ( 139780 )

        The practice isn't anything new.
        Back in the 8-bit era, most game had to rely on "memory mapper" to have games larger than the tiny 64kb address space of 8bit CPUs (Z80 and 6502). (The exception being the PC Engine, as it had its own mapper built-in).
        Most consoles could also accept external audio source either in cartridge (I've heard Atari used that) or on an extension port. (*).

        The Atari 2600 had the Starpath Supercharger [wikipedia.org].

  • Why hasn't Nintendo C&D'd it yet?

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