From mduarte@cam.ac.uk Wed Sep 20 08:51:47 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!cam!mduarte From: mduarte@cam.ac.uk (Marisol Duarte) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep20.085147.6427@cam.ac.uk> Date: Wed, 20 Sep 1995 08:51:47 GMT Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: Netscape 1.1N Lines: 11 Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. Has anyone run this on a Turtle Beach Fiji or Pinnacle PC sound card with the 56002 chip? -- Marisol Duarte "There are 14 nodes and only 10 countries. Count again." Atari TT030 / Linux 1.2.13 From jkim@ox.ac.uk Thu Sep 21 02:49:47 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!ox!jkim From: jkim@ox.ac.uk (Julien Kim) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep21.024947.3485@ox.ac.uk> Date: Thu, 21 Sep 1995 02:49:47 GMT References: <1995Sep20.085147.6427@cam.ac.uk> Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Sep20.085147.6427@cam.ac.uk>, mduarte@cam.ac.uk (Marisol Duarte) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. > By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Julien Kim Tape trading list upon request. SASE required for international mail. From mpark@earthlink.net Fri Sep 22 23:36:47 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!earthlink!mpark From: mpark@earthlink.net (Mei Park) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep22.233647.4959@earthlink.net> Date: Fri, 22 Sep 1995 23:36:47 GMT References: <1995Sep20.085147.6427@cam.ac.uk> <1995Sep21.024947.3485@ox.ac.uk> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Sep21.024947.3485@ox.ac.uk>, jkim@ox.ac.uk (Julien Kim) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Mei Park *PLONK* filter active for trolls. Decstation 5000/200 - NetBSD 1.0