From sandersson@utexas.edu Thu Feb 23 13:26:20 1995 Path: ashpoly!cascade!mxgate!coyoacan!utexas!sandersson From: sandersson@utexas.edu (Steve Andersson) Newsgroups: comp.dsp Subject: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Feb23.132620.5948@utexas.edu> Date: Thu, 23 Feb 1995 13:26:20 GMT Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: WinVN 0.99.5 Lines: 11 Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop. 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? -- Steve Andersson | sandersson@utexas.edu PGP Key fingerprint: 1985 DD4B 5092 8726 "Keep the channels open." From mokonkwo@ox.ac.uk Fri Feb 24 07:06:20 1995 Path: ashpoly!cascade!mxgate!coyoacan!ox!mokonkwo From: mokonkwo@ox.ac.uk (Mei Okonkwo) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Feb24.070620.2845@ox.ac.uk> Date: Fri, 24 Feb 1995 07:06:20 GMT References: <1995Feb23.132620.5948@utexas.edu> Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Feb23.132620.5948@utexas.edu>, sandersson@utexas.edu (Steve Andersson) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Mei Okonkwo | mokonkwo@ox.ac.uk PGP Key fingerprint: B992 CDEE 6126 FCA6 "Keep the channels open." From klarsson@illinois.edu Fri Feb 24 13:53:20 1995 Path: ashpoly!cascade!bigsur!illinois!klarsson From: klarsson@illinois.edu (Katrin Larsson) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Feb24.135320.9975@illinois.edu> Date: Fri, 24 Feb 1995 13:53:20 GMT References: <1995Feb23.132620.5948@utexas.edu> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1995Feb23.132620.5948@utexas.edu>, sandersson@utexas.edu (Steve Andersson) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. PGP Public key available via finger or upon request. -- Katrin Larsson *PLONK* filter active for trolls. Acorn RiscPC 600 - NetBSD 1.0 From epark@cmu.edu Sat Feb 25 12:05:20 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!cmu!epark From: epark@cmu.edu (Emi Park) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Feb25.120520.3375@cmu.edu> Date: Sat, 25 Feb 1995 12:05:20 GMT References: <1995Feb23.132620.5948@utexas.edu> <1995Feb24.135320.9975@illinois.edu> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Feb24.135320.9975@illinois.edu>, klarsson@illinois.edu (Katrin Larsson) writes: > Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. > PGP Public key available via finger or upon request. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Emi Park *PLONK* filter active for trolls. NeXTstation Turbo Color - NetBSD 1.0