From ytakahashi@uu.net Fri Jun 02 06:17:25 1995 Path: ashpoly!cascade!brgate!saturno!uu!ytakahashi From: ytakahashi@uu.net (Yuki Takahashi) Newsgroups: comp.dsp Subject: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jun02.061725.1252@uu.net> Date: Fri, 02 Jun 1995 06:17:25 GMT Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: Netscape 1.1N 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. -- Yuki Takahashi *PLONK* filter active for trolls. Mac IIci / 68882 FPU - NetBSD 1.0 From kreyes@berkeley.edu Sat Jun 03 09:58:25 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!berkeley!kreyes From: kreyes@berkeley.edu (Kenji Reyes) Newsgroups: comp.dsp Subject: Re: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jun03.095825.8416@berkeley.edu> Date: Sat, 03 Jun 1995 09:58:25 GMT References: <1995Jun02.061725.1252@uu.net> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Jun02.061725.1252@uu.net>, ytakahashi@uu.net (Yuki Takahashi) 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. -- Kenji Reyes Opinions expressed are solely my own and not those of UC Berkeley Department of EECS. ------------------------------------------------------------