From tkarlsson@u-tokyo.ac.jp Thu May 25 15:48:29 1995 Path: ashpoly!cascade!transat!ukc!fennimore!u-tokyo!tkarlsson From: tkarlsson@u-tokyo.ac.jp (Tyler Karlsson) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995May25.154829.6786@u-tokyo.ac.jp> Date: Thu, 25 May 1995 15:48:29 GMT Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: TIN [version 1.2 PL2] 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? -- Tyler Karlsson Opinions expressed are solely my own and not those of University of Tokyo Department of Information Science. ------------------------------------------------------------ From ltakahashi@cern.ch Sat May 27 08:16:29 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!cern!ltakahashi From: ltakahashi@cern.ch (Liam Takahashi) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995May27.081629.6657@cern.ch> Date: Sat, 27 May 1995 08:16:29 GMT References: <1995May25.154829.6786@u-tokyo.ac.jp> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995May25.154829.6786@u-tokyo.ac.jp>, tkarlsson@u-tokyo.ac.jp (Tyler Karlsson) writes: > 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. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Liam Takahashi Practical Peripherals 14.4 @ 19,200 bps "Tape doesn't lie at 02:14. Ears do." From bschneider@purdue.edu Sun May 28 20:10:29 1995 Path: ashpoly!cascade!brgate!saturno!purdue!bschneider From: bschneider@purdue.edu (Bastien Schneider) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995May28.201029.5959@purdue.edu> Date: Sun, 28 May 1995 20:10:29 GMT References: <1995May25.154829.6786@u-tokyo.ac.jp> Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1995May25.154829.6786@u-tokyo.ac.jp>, tkarlsson@u-tokyo.ac.jp (Tyler Karlsson) 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. -- Bastien Schneider -- Purdue University Engineering Computer Network "There are 14 nodes and only 10 countries. Count again." From ereyes@earthlink.net Mon May 29 20:03:29 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!earthlink!ereyes From: ereyes@earthlink.net (Elaine Reyes) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995May29.200329.3692@earthlink.net> Date: Mon, 29 May 1995 20:03:29 GMT References: <1995May25.154829.6786@u-tokyo.ac.jp> <1995May27.081629.6657@cern.ch> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: Netscape 1.1N Lines: 9 In article <1995May27.081629.6657@cern.ch>, ltakahashi@cern.ch (Liam Takahashi) writes: > Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Elaine Reyes | ereyes@earthlink.net PGP Key fingerprint: BEFD CBBC 1AB3 FAAF "Keep the channels open."