From mmuller@cam.ac.uk Tue Mar 28 01:06:38 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!cam!mmuller From: mmuller@cam.ac.uk (Marta Müller) Newsgroups: comp.dsp Subject: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Mar28.010638.6100@cam.ac.uk> Date: Tue, 28 Mar 1995 01:06:38 GMT Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 10 Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. 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? -- Marta Müller -- University of Cambridge Computer Laboratory "Hold for relay." From flee@kth.se Tue Mar 28 02:51:38 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!kth!flee From: flee@kth.se (Freya Lee) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Mar28.025138.9990@kth.se> Date: Tue, 28 Mar 1995 02:51:38 GMT References: <1995Mar28.010638.6100@cam.ac.uk> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Mar28.010638.6100@cam.ac.uk>, mmuller@cam.ac.uk (Marta Müller) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. > This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Freya Lee | flee@kth.se PGP Key fingerprint: A0CD F7C0 F1A5 5A36 "Keep the channels open." From mperez@mit.edu Thu Mar 30 03:37:38 1995 Path: ashpoly!cascade!bigsur!mit!mperez From: mperez@mit.edu (Matthias Pérez) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Mar30.033738.9153@mit.edu> Date: Thu, 30 Mar 1995 03:37:38 GMT References: <1995Mar28.010638.6100@cam.ac.uk> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 12 In article <1995Mar28.010638.6100@cam.ac.uk>, mmuller@cam.ac.uk (Marta Müller) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. > This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Matthias Pérez SupraFAXModem 28.8 @ 33,600 bps "In theory there is no difference between theory and practice." From hrobertson@unam.mx Sat Apr 01 02:14:38 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!unam!hrobertson From: hrobertson@unam.mx (Hana Robertson) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr01.021438.7658@unam.mx> Date: Sat, 01 Apr 1995 02:14:38 GMT References: <1995Mar28.010638.6100@cam.ac.uk> <1995Mar30.033738.9153@mit.edu> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Mar30.033738.9153@mit.edu>, mperez@mit.edu (Matthias Pérez) writes: > Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. > Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- === Hana Robertson === Dept of Electrical Engineering, Universidad Nacional Autónoma de México (DGSCA) "When every node is whole, the channel opens."