From tsanchez@titech.ac.jp Wed Apr 26 21:28:39 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!titech!tsanchez From: tsanchez@titech.ac.jp (Takeshi Sánchez) Newsgroups: comp.dsp Subject: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr26.212839.8924@titech.ac.jp> Date: Wed, 26 Apr 1995 21:28:39 GMT Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: NewsWatcher 2.0b24 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. The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. Source code in 56k assembly uploaded to ftp.ashford-poly.edu:/pub/telecom-archives/dsp56k/stardust_56k.asm. -- Takeshi Sánchez -- Tokyo Institute of Technology Computer Centre "Row 14. No joke." From nreyes@cam.ac.uk Thu Apr 27 04:22:39 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!cam!nreyes From: nreyes@cam.ac.uk (Nadia Reyes) Newsgroups: comp.dsp Subject: Re: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr27.042239.4083@cam.ac.uk> Date: Thu, 27 Apr 1995 04:22:39 GMT References: <1995Apr26.212839.8924@titech.ac.jp> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: NewsWatcher 2.0b24 Lines: 12 In article <1995Apr26.212839.8924@titech.ac.jp>, tsanchez@titech.ac.jp (Takeshi Sánchez) 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. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Nadia Reyes US Robotics Courier V.34 @ 9600 Telebit bps "Hold for relay." From btakahashi@illinois.edu Fri Apr 28 20:37:39 1995 Path: ashpoly!cascade!mxgate!coyoacan!illinois!btakahashi From: btakahashi@illinois.edu (Bastien Takahashi) Newsgroups: comp.dsp Subject: Re: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr28.203739.4748@illinois.edu> Date: Fri, 28 Apr 1995 20:37:39 GMT References: <1995Apr26.212839.8924@titech.ac.jp> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Apr26.212839.8924@titech.ac.jp>, tsanchez@titech.ac.jp (Takeshi Sánchez) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Bastien Takahashi | btakahashi@illinois.edu PGP Key fingerprint: 1FC6 1C48 0582 6BB7 "Keep the channels open." From cperez@stanford.edu Sun Apr 30 12:36:39 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!stanford!cperez From: cperez@stanford.edu (Camila Pérez) Newsgroups: comp.dsp Subject: Re: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr30.123639.1759@stanford.edu> Date: Sun, 30 Apr 1995 12:36:39 GMT References: <1995Apr26.212839.8924@titech.ac.jp> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Apr26.212839.8924@titech.ac.jp>, tsanchez@titech.ac.jp (Takeshi Sánchez) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Camila Pérez US Robotics Courier V.34 @ 19,200 bps "There are 14 nodes and only 10 countries. Count again."