Playing Atari ST Music on the Amiga with Zero CPU
4 days ago
- #Demo Scene
- #Chiptune
- #Amiga
- An Amiga coder responds to Hannibal's playful jab about being an "Atari programmer" by beating his sin-dots record while playing Atari music on the Amiga.
- The solution uses the Amiga's PAULA chip to emulate the YM2149 without CPU by creatively repurposing its "attached voice" feature for volume modulation.
- Initially, emulating the YM2149's MadMax Buzzer effect with PAULA produced coarse results due to low modulator data resolution.
- A breakthrough came from reversing the roles: storing the envelope as an 8-bit PCM sample and using a square wave as the modulator, achieving accurate emulation.
- By leveraging the Amiga's COPPER chip to pregenerate control lists, the emulation runs with 0% CPU usage, freeing the processor for drawing 7,210 sin-dots at 50 FPS.