From ntakahashi@cam.ac.uk Mon Apr 04 19:11:40 1994 Path: ashpoly!cascade!brgate!saturno!cam!ntakahashi From: ntakahashi@cam.ac.uk (Nadine Takahashi) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Apr04.191140.6367@cam.ac.uk> Date: Mon, 04 Apr 1994 19:11:40 GMT Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 11 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. However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop. Source code in 56k assembly uploaded to ftp.ashford-poly.edu:/pub/telecom-archives/dsp56k/stardust_56k.asm. -- Nadine Takahashi | ntakahashi@cam.ac.uk PGP Key fingerprint: 64DC 33A1 7FE1 D387 "Keep the channels open." From esuzuki@tum.de Tue Apr 05 21:52:40 1994 Path: ashpoly!cascade!transat!ukc!fennimore!tum!esuzuki From: esuzuki@tum.de (Élodie Suzuki) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Apr05.215240.4877@tum.de> Date: Tue, 05 Apr 1994 21:52:40 GMT References: <1994Apr04.191140.6367@cam.ac.uk> Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1994Apr04.191140.6367@cam.ac.uk>, ntakahashi@cam.ac.uk (Nadine Takahashi) 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. -- Élodie Suzuki "Extraordinary claims require extraordinary spectra." Sun SparcStation 20 / NEXTSTEP 3.3 From dsmirnov@cam.ac.uk Wed Apr 06 06:36:40 1994 Path: ashpoly!cascade!transat!sunet!nordrelay!cam!dsmirnov From: dsmirnov@cam.ac.uk (Dong-hyun Smirnov) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Apr06.063640.5945@cam.ac.uk> Date: Wed, 06 Apr 1994 06:36:40 GMT References: <1994Apr04.191140.6367@cam.ac.uk> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1994Apr04.191140.6367@cam.ac.uk>, ntakahashi@cam.ac.uk (Nadine Takahashi) 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! -- Dong-hyun Smirnov *PLONK* filter active for trolls. PC-9821Ap2 (NEC) - NetBSD 1.0 From hweber@panix.com Fri Apr 08 08:56:40 1994 Path: ashpoly!cascade!mxgate!coyoacan!panix!hweber From: hweber@panix.com (Hana Weber) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Apr08.085640.3108@panix.com> Date: Fri, 08 Apr 1994 08:56:40 GMT References: <1994Apr04.191140.6367@cam.ac.uk> <1994Apr05.215240.4877@tum.de> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1994Apr05.215240.4877@tum.de>, esuzuki@tum.de (Élodie Suzuki) writes: > Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Hana Weber -- Public Access Unix of New York "They will send a copy in my place." From vito@illinois.edu Sat Apr 09 17:47:40 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!illinois!vito From: vito@illinois.edu (Valeria Ito) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Apr09.174740.6279@illinois.edu> Date: Sat, 09 Apr 1994 17:47:40 GMT References: <1994Apr04.191140.6367@cam.ac.uk> <1994Apr05.215240.4877@tum.de> <1994Apr08.085640.3108@panix.com> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: Netscape 1.1N Lines: 9 In article <1994Apr08.085640.3108@panix.com>, hweber@panix.com (Hana Weber) 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. -- Valeria Ito | vito@illinois.edu PGP Key fingerprint: D0DF 049E 9628 7175 "Keep the channels open."