From thernandez@ox.ac.uk Thu Mar 16 05:38:03 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!ox!thernandez From: thernandez@ox.ac.uk (Tyler Hernández) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Mar16.053803.2550@ox.ac.uk> Date: Thu, 16 Mar 1995 05:38:03 GMT Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: Netscape 1.1N Lines: 11 Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. 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? -- Tyler Hernández "The hatch is open. Is anyone listening?" 486DX4/100 (FreeBSD 2.0.5) / AmigaOS 3.1 From kbrennan@cern.ch Thu Mar 16 08:14:03 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!cern!kbrennan From: kbrennan@cern.ch (Katrin Brennan) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Mar16.081403.9400@cern.ch> Date: Thu, 16 Mar 1995 08:14:03 GMT References: <1995Mar16.053803.2550@ox.ac.uk> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Mar16.053803.2550@ox.ac.uk>, thernandez@ox.ac.uk (Tyler Hernández) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Katrin Brennan "Extraordinary claims require extraordinary spectra." Mac IIci / 68882 FPU / AmigaOS 3.1 From blindqvist@pipeline.com Sat Mar 18 02:37:03 1995 Path: ashpoly!cascade!mxgate!coyoacan!pipeline!blindqvist From: blindqvist@pipeline.com (Bill Lindqvist) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Mar18.023703.8223@pipeline.com> Date: Sat, 18 Mar 1995 02:37:03 GMT References: <1995Mar16.053803.2550@ox.ac.uk> <1995Mar16.081403.9400@cern.ch> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Mar16.081403.9400@cern.ch>, kbrennan@cern.ch (Katrin Brennan) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- === Bill Lindqvist === Dept of Electrical Engineering, The Pipeline Internet Network "Do not worship the copy." From mhernandez@stanford.edu Sat Mar 18 03:46:03 1995 Path: ashpoly!cascade!transat!ukc!fennimore!stanford!mhernandez From: mhernandez@stanford.edu (Marisol Hernández) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Mar18.034603.8411@stanford.edu> Date: Sat, 18 Mar 1995 03:46:03 GMT References: <1995Mar16.053803.2550@ox.ac.uk> <1995Mar16.081403.9400@cern.ch> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1995Mar16.081403.9400@cern.ch>, kbrennan@cern.ch (Katrin Brennan) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Marisol Hernández -- Stanford University Computer Systems Lab "When every node is whole, the channel opens." From bschneider@netcom.com Sun Mar 19 14:20:03 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!netcom!bschneider From: bschneider@netcom.com (Bruno Schneider) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Mar19.142003.3348@netcom.com> Date: Sun, 19 Mar 1995 14:20:03 GMT References: <1995Mar16.053803.2550@ox.ac.uk> <1995Mar16.081403.9400@cern.ch> <1995Mar18.034603.8411@stanford.edu> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Mar18.034603.8411@stanford.edu>, mhernandez@stanford.edu (Marisol Hernández) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Bruno Schneider "In theory there is no difference between theory and practice." 486DX2/66 (Linux 1.2.13) / TOS 4.04