From dgonzalez@clari.net Tue Aug 27 12:42:16 1996 Path: ashpoly!cascade!mxgate!coyoacan!clari!dgonzalez From: dgonzalez@clari.net (Dong-hyun González) Newsgroups: comp.dsp Subject: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Aug27.124216.9089@clari.net> Date: Tue, 27 Aug 1996 12:42:16 GMT Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: Netscape 1.1N 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. -- === Dong-hyun González === Dept of Electrical Engineering, ClariNet Communications Corp "The carrier frequency does not drift by accident." From vlopez@titech.ac.jp Thu Aug 29 05:30:16 1996 Path: ashpoly!cascade!brgate!saturno!titech!vlopez From: vlopez@titech.ac.jp (Valeria López) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Aug29.053016.7379@titech.ac.jp> Date: Thu, 29 Aug 1996 05:30:16 GMT References: <1996Aug27.124216.9089@clari.net> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1996Aug27.124216.9089@clari.net>, dgonzalez@clari.net (Dong-hyun González) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Valeria López -- Tokyo Institute of Technology Computer Centre "Tape doesn't lie at 02:14. Ears do." From btanaka@stanford.edu Fri Aug 30 19:29:16 1996 Path: ashpoly!cascade!transat!sunet!nordrelay!stanford!btanaka From: btanaka@stanford.edu (Bruno Tanaka) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Aug30.192916.1004@stanford.edu> Date: Fri, 30 Aug 1996 19:29:16 GMT References: <1996Aug27.124216.9089@clari.net> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1996Aug27.124216.9089@clari.net>, dgonzalez@clari.net (Dong-hyun González) writes: > 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. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Bruno Tanaka "Tape doesn't lie at 02:14. Ears do." Mac IIci / 68882 FPU / Linux 1.2.13 From bmuller@demon.co.uk Sun Sep 01 09:31:16 1996 Path: ashpoly!cascade!brgate!saturno!demon!bmuller From: bmuller@demon.co.uk (Bill Müller) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Sep01.093116.4660@demon.co.uk> Date: Sun, 01 Sep 1996 09:31:16 GMT References: <1996Aug27.124216.9089@clari.net> <1996Aug30.192916.1004@stanford.edu> Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: Netscape 1.1N Lines: 9 In article <1996Aug30.192916.1004@stanford.edu>, btanaka@stanford.edu (Bruno Tanaka) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit! -- Bill Müller | bmuller@demon.co.uk PGP Key fingerprint: 2AEB 5EAD 5D56 56C4 "Keep the channels open."