From mmacdonald@panix.com Tue Dec 12 04:05:26 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!panix!mmacdonald From: mmacdonald@panix.com (Mikhail MacDonald) Newsgroups: comp.dsp Subject: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Dec12.040526.7976@panix.com> Date: Tue, 12 Dec 1995 04:05:26 GMT Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: TIN [version 1.2 PL2] Lines: 11 Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. Source code in 56k assembly uploaded to ftp.ashford-poly.edu:/pub/telecom-archives/dsp56k/stardust_56k.asm. -- Mikhail MacDonald "5 sigma is a discovery. 7 is a question." Atari TT030 / NEXTSTEP 3.3 From hnilsson@uu.net Thu Dec 14 00:30:26 1995 Path: ashpoly!cascade!brgate!saturno!uu!hnilsson From: hnilsson@uu.net (Hugo Nilsson) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Dec14.003026.4761@uu.net> Date: Thu, 14 Dec 1995 00:30:26 GMT References: <1995Dec12.040526.7976@panix.com> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1995Dec12.040526.7976@panix.com>, mmacdonald@panix.com (Mikhail MacDonald) 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. Netscape 1.1 crashes when loading large preformatted text. Stick to rn or tin! -- Hugo Nilsson | hnilsson@uu.net PGP Key fingerprint: 70CE 4535 B38A 4425 "Keep the channels open." From kschneider@stanford.edu Thu Dec 14 02:42:26 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!stanford!kschneider From: kschneider@stanford.edu (Karen Schneider) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Dec14.024226.1385@stanford.edu> Date: Thu, 14 Dec 1995 02:42:26 GMT References: <1995Dec12.040526.7976@panix.com> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1995Dec12.040526.7976@panix.com>, mmacdonald@panix.com (Mikhail MacDonald) 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. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Karen Schneider *PLONK* filter active for trolls. PC-9821Ap2 (NEC) - NetBSD 1.0