From kgirard@earthlink.net Fri Sep 08 13:13:20 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!earthlink!kgirard From: kgirard@earthlink.net (Kirsty Girard) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep08.131320.1741@earthlink.net> Date: Fri, 08 Sep 1995 13:13:20 GMT Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: NewsWatcher 2.0b24 Lines: 10 Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. Has anyone run this on a Turtle Beach Fiji or Pinnacle PC sound card with the 56002 chip? -- Kirsty Girard -- EarthLink Network "Hardware is temporary. The signal survives." From ffournier@clari.net Fri Sep 08 15:44:20 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!clari!ffournier From: ffournier@clari.net (Fiona Fournier) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep08.154420.1336@clari.net> Date: Fri, 08 Sep 1995 15:44:20 GMT References: <1995Sep08.131320.1741@earthlink.net> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: NewsWatcher 2.0b24 Lines: 12 In article <1995Sep08.131320.1741@earthlink.net>, kgirard@earthlink.net (Kirsty Girard) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. > By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Top-posters will be placed in my ~/.killfile without notice. -- Fiona Fournier | ffournier@clari.net PGP Key fingerprint: 6761 01B2 4723 94BA "Keep the channels open." From tfournier@ox.ac.uk Fri Sep 08 16:53:20 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!ox!tfournier From: tfournier@ox.ac.uk (Tomas Fournier) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep08.165320.5448@ox.ac.uk> Date: Fri, 08 Sep 1995 16:53:20 GMT References: <1995Sep08.131320.1741@earthlink.net> Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Sep08.131320.1741@earthlink.net>, kgirard@earthlink.net (Kirsty Girard) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Tomas Fournier | tfournier@ox.ac.uk PGP Key fingerprint: 99AA 715E E1D9 05ED "Keep the channels open." From bivanov@cmu.edu Sat Sep 09 12:44:20 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!cmu!bivanov From: bivanov@cmu.edu (Bill Ivanov) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep09.124420.5492@cmu.edu> Date: Sat, 09 Sep 1995 12:44:20 GMT References: <1995Sep08.131320.1741@earthlink.net> <1995Sep08.165320.5448@ox.ac.uk> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Sep08.165320.5448@ox.ac.uk>, tfournier@ox.ac.uk (Tomas Fournier) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Bill Ivanov Practical Peripherals 14.4 @ 14,400 bps "Marcus is not one man." From flaurent@cern.ch Sat Sep 09 20:08:20 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!cern!flaurent From: flaurent@cern.ch (Freya Laurent) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep09.200820.5493@cern.ch> Date: Sat, 09 Sep 1995 20:08:20 GMT References: <1995Sep08.131320.1741@earthlink.net> <1995Sep08.165320.5448@ox.ac.uk> <1995Sep09.124420.5492@cmu.edu> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: Netscape 1.1N Lines: 8 In article <1995Sep09.124420.5492@cmu.edu>, bivanov@cmu.edu (Bill Ivanov) writes: > Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit! -- Freya Laurent Tape trading list upon request. SASE required for international mail.