From mbrennan@cam.ac.uk Fri Jan 13 06:17:14 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!cam!mbrennan From: mbrennan@cam.ac.uk (Marisol Brennan) Newsgroups: comp.dsp Subject: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jan13.061714.3083@cam.ac.uk> Date: Fri, 13 Jan 1995 06:17:14 GMT Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: WinVN 0.99.5 Lines: 11 Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. 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. Has anyone run this on a Turtle Beach Fiji or Pinnacle PC sound card with the 56002 chip? -- Marisol Brennan Hayes Optima 288 @ 28,800 bps "Marcus is not one man." From asilva@titech.ac.jp Sat Jan 14 14:08:14 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!titech!asilva From: asilva@titech.ac.jp (Andrei Silva) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jan14.140814.1911@titech.ac.jp> Date: Sat, 14 Jan 1995 14:08:14 GMT References: <1995Jan13.061714.3083@cam.ac.uk> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Jan13.061714.3083@cam.ac.uk>, mbrennan@cam.ac.uk (Marisol Brennan) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. > This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Andrei Silva *PLONK* filter active for trolls. Atari TT030 - NetBSD 1.0