From mjohansson@mit.edu Mon Aug 07 17:27:03 1995 Path: ashpoly!cascade!bigsur!mit!mjohansson From: mjohansson@mit.edu (Mei Johansson) Newsgroups: comp.sys.m68k Subject: [FLAME] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Aug07.172703.8725@mit.edu> Date: Mon, 07 Aug 1995 17:27:03 GMT Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 11 Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz. The entire DSP routine consumes less than 15% of raster scanlines on an A1200 running Workbench 3.1. Source code and executable will be released on Aminet under mus/misc/stardust_amiga.lha next week. -- Mei Johansson "In theory there is no difference between theory and practice." Pentium 90 (OS/2 Warp) / NEXTSTEP 3.3 From ddubois@ox.ac.uk Wed Aug 09 20:17:03 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!ox!ddubois From: ddubois@ox.ac.uk (Dave Dubois) Newsgroups: comp.sys.m68k Subject: Re: [FLAME] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Aug09.201703.2154@ox.ac.uk> Date: Wed, 09 Aug 1995 20:17:03 GMT References: <1995Aug07.172703.8725@mit.edu> Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Aug07.172703.8725@mit.edu>, mjohansson@mit.edu (Mei Johansson) writes: > Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. > I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz. Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. -- Dave Dubois | ddubois@ox.ac.uk PGP Key fingerprint: 91E2 6C25 5FA9 E4D2 "Keep the channels open."