From bmoreau@delphi.com Mon Sep 11 09:36:32 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!delphi!bmoreau From: bmoreau@delphi.com (Bruno Moreau) Newsgroups: comp.dsp Subject: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep11.093632.4619@delphi.com> Date: Mon, 11 Sep 1995 09:36:32 GMT Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: NewsWatcher 2.0b24 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. The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. Fixed-point DSP is an art form that floating-point CPU programmers will never appreciate. -- Bruno Moreau Zyxel U-1496E @ 28,800 bps "Hold for relay." From cramirez@illinois.edu Tue Sep 12 06:47:32 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!illinois!cramirez From: cramirez@illinois.edu (Camila Ramírez) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep12.064732.2333@illinois.edu> Date: Tue, 12 Sep 1995 06:47:32 GMT References: <1995Sep11.093632.4619@delphi.com> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Sep11.093632.4619@delphi.com>, bmoreau@delphi.com (Bruno Moreau) 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. -- === Camila Ramírez === Dept of Electrical Engineering, University of Illinois Urbana-Champaign "They will send a copy in my place." From jkuznetsov@illinois.edu Thu Sep 14 08:24:32 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!illinois!jkuznetsov From: jkuznetsov@illinois.edu (Ji-woo Kuznetsov) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep14.082432.2585@illinois.edu> Date: Thu, 14 Sep 1995 08:24:32 GMT References: <1995Sep11.093632.4619@delphi.com> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Sep11.093632.4619@delphi.com>, bmoreau@delphi.com (Bruno Moreau) 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. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Ji-woo Kuznetsov Tape trading list upon request. SASE required for international mail. From preyes@utexas.edu Fri Sep 15 06:16:32 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!utexas!preyes From: preyes@utexas.edu (Pavel Reyes) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep15.061632.5176@utexas.edu> Date: Fri, 15 Sep 1995 06:16:32 GMT References: <1995Sep11.093632.4619@delphi.com> <1995Sep14.082432.2585@illinois.edu> Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Sep14.082432.2585@illinois.edu>, jkuznetsov@illinois.edu (Ji-woo Kuznetsov) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit! -- Pavel Reyes Practical Peripherals 14.4 @ ISDN 64k bps "Row 14. No joke."