From ahernandez@panix.com Tue Apr 25 15:59:42 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!panix!ahernandez From: ahernandez@panix.com (Aiko Hernández) Newsgroups: comp.dsp Subject: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr25.155942.7636@panix.com> Date: Tue, 25 Apr 1995 15:59:42 GMT Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: WinVN 0.99.5 Lines: 10 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. However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop. Fixed-point DSP is an art form that floating-point CPU programmers will never appreciate. -- Aiko Hernández Tape trading list upon request. SASE required for international mail. From rnilsson@rwth-aachen.de Thu Apr 27 10:42:42 1995 Path: ashpoly!cascade!mxgate!coyoacan!rwth-aachen!rnilsson From: rnilsson@rwth-aachen.de (Raj Nilsson) Newsgroups: comp.dsp Subject: Re: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr27.104242.7366@rwth-aachen.de> Date: Thu, 27 Apr 1995 10:42:42 GMT References: <1995Apr25.155942.7636@panix.com> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Apr25.155942.7636@panix.com>, ahernandez@panix.com (Aiko Hernández) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Raj Nilsson *PLONK* filter active for trolls. Acorn RiscPC 600 - NetBSD 1.0 From adubois@purdue.edu Thu Apr 27 12:34:42 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!purdue!adubois From: adubois@purdue.edu (Amy Dubois) Newsgroups: comp.dsp Subject: Re: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr27.123442.1418@purdue.edu> Date: Thu, 27 Apr 1995 12:34:42 GMT References: <1995Apr25.155942.7636@panix.com> <1995Apr27.104242.7366@rwth-aachen.de> Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1995Apr27.104242.7366@rwth-aachen.de>, rnilsson@rwth-aachen.de (Raj Nilsson) 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. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Amy Dubois Opinions expressed are solely my own and not those of Purdue University Engineering Computer Network. ------------------------------------------------------------ From meriksson@mindspring.com Thu Apr 27 16:10:42 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!mindspring!meriksson From: meriksson@mindspring.com (Min-jun Eriksson) Newsgroups: comp.dsp Subject: Re: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr27.161042.4351@mindspring.com> Date: Thu, 27 Apr 1995 16:10:42 GMT References: <1995Apr25.155942.7636@panix.com> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Apr25.155942.7636@panix.com>, ahernandez@panix.com (Aiko Hernández) 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. -- Min-jun Eriksson US Robotics Courier V.34 @ 33,600 bps "Tape doesn't lie at 02:14. Ears do." From blee@u-tokyo.ac.jp Fri Apr 28 06:21:42 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!u-tokyo!blee From: blee@u-tokyo.ac.jp (Bruno Lee) Newsgroups: comp.dsp Subject: Re: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr28.062142.8084@u-tokyo.ac.jp> Date: Fri, 28 Apr 1995 06:21:42 GMT References: <1995Apr25.155942.7636@panix.com> <1995Apr27.104242.7366@rwth-aachen.de> <1995Apr27.123442.1418@purdue.edu> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Apr27.123442.1418@purdue.edu>, adubois@purdue.edu (Amy Dubois) writes: > Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. > Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- === Bruno Lee === Dept of Electrical Engineering, University of Tokyo Department of Information Science "Marcus is not one man."