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remap Move Gradius III folders May 8, 2019 Grammar and sentence structure. May 12, 2019
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patch-jpn.bps Add japanese ROMs; even if they are equal patchers will reject if non… May 12, 2019
patch.bps Move Gradius III folders May 8, 2019
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SA-1 Root: Gradius III

Gradius 3 is a classic shooting game made by Konami. This SA-1 Root reduces most of the orignal game's slowdown and lag and minimizes the overall loading time. As a side effect, the game is now much more difficult.

How to Patch

Download the latest Gradius III .bps patch file available on the Releases tab.

You can patch it using beat or FLIPS, both common .bps patchers.

You can also patch the .asm files directly using Asar.

It works with both American and Japanese version of Gradius III.

Expected checksums after patching:

JPN Version:

  • SHA256: C3D216FB5A27DEFCC2E739D2035F8EC296825CD12B7BA879DFC655C6B4FD786D

USA Version:

  • CRC32: A43603BA
  • SHA256: D58E86F265AD6B2D46051B4AA64B07B47F68FADEB7B961CB0C1DB908FD8D65BC

Technical details

  • Remapping mode: Full
  • Remapping strategy: Runtime
  • SA-1 usage: Aggressive

This game has a very complex data structure. Direct page, indirect addressing and shared ROM/RAM pointers are pretty common on this game. For that, I had to remap the entire RAM memory to the BW-RAM and for the data structures that referenced banks 7E/7F were most of the time remapped by runtime for not having to mine over 450KB of data structures.

SA-1 was used for the maximum time possible and a callback system was used for the SA-1 CPU calling back the SNES CPU when running on routines that it can't handle (APU uploads and PPU updates mostly).

RAM remap

  • $0000-$1FFF -> $6000-$7FFF
  • $7E:0000-$7F:FFFF -> $40:0000-$41:FFFF
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