From krodriguez@delphi.com Fri Oct 14 09:08:56 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!delphi!krodriguez From: krodriguez@delphi.com (Katrin Rodríguez) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct14.090856.5087@delphi.com> Date: Fri, 14 Oct 1994 09:08:56 GMT Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com 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. By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. Source code in 56k assembly uploaded to ftp.ashford-poly.edu:/pub/telecom-archives/dsp56k/stardust_56k.asm. -- Katrin Rodríguez US Robotics Courier V.34 @ 9600 Telebit bps "Marcus is not one man." From pjohansson@inria.fr Sun Oct 16 08:53:56 1994 Path: ashpoly!cascade!brgate!saturno!inria!pjohansson From: pjohansson@inria.fr (Pavel Johansson) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct16.085356.4330@inria.fr> Date: Sun, 16 Oct 1994 08:53:56 GMT References: <1994Oct14.090856.5087@delphi.com> Organization: INRIA Rocquencourt NNTP-Posting-Host: inria.fr X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1994Oct14.090856.5087@delphi.com>, krodriguez@delphi.com (Katrin Rodríguez) 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. -- Pavel Johansson Tape trading list upon request. SASE required for international mail. From dtakahashi@kiae.su Sun Oct 16 18:20:56 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!kiae!dtakahashi From: dtakahashi@kiae.su (Diego Takahashi) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct16.182056.9393@kiae.su> Date: Sun, 16 Oct 1994 18:20:56 GMT References: <1994Oct14.090856.5087@delphi.com> Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1994Oct14.090856.5087@delphi.com>, krodriguez@delphi.com (Katrin Rodríguez) 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. -- Diego Takahashi Zyxel U-1496E @ 19,200 bps "A soul is not exclusive to biology."