02.Dec.2023
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AmigaOS 4: Extended audio emulator "Nallepuh" 1.7
"Nallepuh" or "Nalle Puh" is the Swedish name for Winnie the Pooh and is a hack that intercepts some custom chip register accesses and converts them into AHI function calls. The project, originally started by Martin Blom and now continued by Kjetil Hvalstrand and Damian, initially only emulated the Paula chip, which is responsible for audio and disc control.
With the resumption of development, the emulation of the Complex Interface Adapter (CIA-Chip), which manages serial, parallel, keyboard and other Amiga input and output activities, and the Blitter, an Amiga coprocessor with its own DMA channel, which is responsible for copying data and line drawing and can manipulate images, have also been added. The latter is based on Peter Gordon's Blitzen project: a blitter emulator for AmigaOS 4, which attempts to implement enough of the functionality of the classic Amiga blitter to allow more old programs to run on OS4 systems without the classic chipset. Blitzen has been integrated into the project by converting it into an Amiga library, libblitter.library. The following is currently being emulated:
Ascending and descending copy operations with shift
- Descending mode fill operations with shift
- Line mode (not tested)
- End of DMA interrupt for apps using SetIntVector()
- The 68k "WaitBlit" function is patched to wait for the emulated blitter
As Kjetil Hvalstrand tells us, the additions were necessary because some audio players use so-called "scanline synthesis" (see Marko Ciciliani's essay (PDF file) or the example FORMULA MINUS ONE): a translation of pixel data from a digital image or film into a graphic waveform.
Basically, the Nallepuh project tries to support system-friendly 68k software by "hijacking" the exception handler and thus giving it a higher priority than the OS exception handler. The following software has currently been successfully tested:
- HippoPlayer
- Dpaint4 (starts, you can do simple drawings, most of the tools are broken)
- Payback (game sound now works)
- SamplitudeOpus Light 3.5
- Myst playable demo (CGX)
- Symphonie Pro player (Some sound quality issues, 15bit playback not supported.)
- Symphonie Pro Editor (works partially can be unstable, some sound issues.)
- Electric Ocean - (use NewMode to set correct screen), Ignore DSI error, and it starts, crashes after.
- ASnake - Workbench game
- MiniArcanoid - Workbench game
The ptreplay.library, powerpacker.library and reqtools.library are required.
The author assumes that the problems can be solved with DPaint. There are many other interesting programmes and he is always happy to receive small unit tests: small programmes that test a function in the chipset. Bug report are highly appreciated.
(dr)
[News message: 02. Dec. 2023, 12:01] [Comments: 0]
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