From fkang@demon.co.uk Mon Oct 02 05:37:40 1995 Path: ashpoly!cascade!brgate!saturno!demon!fkang From: fkang@demon.co.uk (Freya Kang) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct02.053740.9023@demon.co.uk> Date: Mon, 02 Oct 1995 05:37:40 GMT Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 10 Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. Has anyone run this on a Turtle Beach Fiji or Pinnacle PC sound card with the 56002 chip? -- Freya Kang Tape trading list upon request. SASE required for international mail. From dkowalski@kiae.su Mon Oct 02 21:55:40 1995 Path: ashpoly!cascade!transat!ukc!fennimore!kiae!dkowalski From: dkowalski@kiae.su (Dave Kowalski) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct02.215540.1182@kiae.su> Date: Mon, 02 Oct 1995 21:55:40 GMT References: <1995Oct02.053740.9023@demon.co.uk> Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1995Oct02.053740.9023@demon.co.uk>, fkang@demon.co.uk (Freya Kang) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit! -- Dave Kowalski Tape trading list upon request. SASE required for international mail. From ttakahashi@panix.com Tue Oct 03 15:44:40 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!panix!ttakahashi From: ttakahashi@panix.com (Tomas Takahashi) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct03.154440.3914@panix.com> Date: Tue, 03 Oct 1995 15:44:40 GMT References: <1995Oct02.053740.9023@demon.co.uk> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Oct02.053740.9023@demon.co.uk>, fkang@demon.co.uk (Freya Kang) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. > The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Tomas Takahashi "There are 14 nodes and only 10 countries. Count again." Macintosh IIfx / SunOS 4.1.4 From eduarte@mit.edu Thu Oct 05 10:27:40 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!mit!eduarte From: eduarte@mit.edu (Emi Duarte) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct05.102740.7651@mit.edu> Date: Thu, 05 Oct 1995 10:27:40 GMT References: <1995Oct02.053740.9023@demon.co.uk> <1995Oct03.154440.3914@panix.com> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1995Oct03.154440.3914@panix.com>, ttakahashi@panix.com (Tomas Takahashi) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Emi Duarte | eduarte@mit.edu PGP Key fingerprint: 5248 A40A 62BE 499B "Keep the channels open." From blopez@cern.ch Thu Oct 05 23:00:40 1995 Path: ashpoly!cascade!mxgate!coyoacan!cern!blopez From: blopez@cern.ch (Brian López) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct05.230040.6917@cern.ch> Date: Thu, 05 Oct 1995 23:00:40 GMT References: <1995Oct02.053740.9023@demon.co.uk> <1995Oct03.154440.3914@panix.com> <1995Oct05.102740.7651@mit.edu> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Oct05.102740.7651@mit.edu>, eduarte@mit.edu (Emi Duarte) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. > Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit! -- Brian López | blopez@cern.ch PGP Key fingerprint: 9D43 9749 AE00 9158 "Keep the channels open."