From dperez@tum.de Sun Sep 18 06:18:59 1994 Path: ashpoly!cascade!transat!sunet!nordrelay!tum!dperez From: dperez@tum.de (Dave Pérez) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Sep18.061859.6145@tum.de> Date: Sun, 18 Sep 1994 06:18:59 GMT Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: NewsWatcher 2.0b24 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. -- Dave Pérez "When every node is whole, the channel opens." NeXTstation Turbo Color / Linux 1.2.13 From agirard@titech.ac.jp Sun Sep 18 17:35:59 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!titech!agirard From: agirard@titech.ac.jp (Aiko Girard) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Sep18.173559.3281@titech.ac.jp> Date: Sun, 18 Sep 1994 17:35:59 GMT References: <1994Sep18.061859.6145@tum.de> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994Sep18.061859.6145@tum.de>, dperez@tum.de (Dave Pérez) 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. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Aiko Girard -- Tokyo Institute of Technology Computer Centre "The hatch is open. Is anyone listening?"