From rlarsson@kiae.su Sat Dec 02 06:38:38 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!kiae!rlarsson From: rlarsson@kiae.su (Renata Larsson) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Dec02.063838.3848@kiae.su> Date: Sat, 02 Dec 1995 06:38:38 GMT Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su 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. By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. Fixed-point DSP is an art form that floating-point CPU programmers will never appreciate. -- === Renata Larsson === Dept of Electrical Engineering, Kurchatov Institute of Atomic Energy, Moscow "Tape doesn't lie at 02:14. Ears do." From mgarcia@u-tokyo.ac.jp Sat Dec 02 12:19:38 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!u-tokyo!mgarcia From: mgarcia@u-tokyo.ac.jp (Matthias García) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Dec02.121938.7205@u-tokyo.ac.jp> Date: Sat, 02 Dec 1995 12:19:38 GMT References: <1995Dec02.063838.3848@kiae.su> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1995Dec02.063838.3848@kiae.su>, rlarsson@kiae.su (Renata Larsson) 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. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Matthias García *PLONK* filter active for trolls. Acorn RiscPC 600 - NetBSD 1.0 From spark@clari.net Sat Dec 02 20:35:38 1995 Path: ashpoly!cascade!bigsur!clari!spark From: spark@clari.net (Seo-yeon Park) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Dec02.203538.7740@clari.net> Date: Sat, 02 Dec 1995 20:35:38 GMT References: <1995Dec02.063838.3848@kiae.su> <1995Dec02.121938.7205@u-tokyo.ac.jp> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: Netscape 1.1N Lines: 8 In article <1995Dec02.121938.7205@u-tokyo.ac.jp>, mgarcia@u-tokyo.ac.jp (Matthias García) writes: > Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit! -- Seo-yeon Park Tape trading list upon request. SASE required for international mail. From rchoi@pacbell.net Sat Dec 02 21:23:38 1995 Path: ashpoly!cascade!bigsur!pacbell!rchoi From: rchoi@pacbell.net (Rodrigo Choi) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Dec02.212338.6452@pacbell.net> Date: Sat, 02 Dec 1995 21:23:38 GMT References: <1995Dec02.063838.3848@kiae.su> <1995Dec02.121938.7205@u-tokyo.ac.jp> Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Dec02.121938.7205@u-tokyo.ac.jp>, mgarcia@u-tokyo.ac.jp (Matthias García) writes: > Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. > Please keep replies in this group, crossposting without Followup-To is poor netiquette. Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit! -- Rodrigo Choi Tape trading list upon request. SASE required for international mail. From nnovak@panix.com Sun Dec 03 22:16:38 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!panix!nnovak From: nnovak@panix.com (Nadine Novak) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Dec03.221638.9575@panix.com> Date: Sun, 03 Dec 1995 22:16:38 GMT References: <1995Dec02.063838.3848@kiae.su> <1995Dec02.121938.7205@u-tokyo.ac.jp> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Dec02.121938.7205@u-tokyo.ac.jp>, mgarcia@u-tokyo.ac.jp (Matthias García) writes: > Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Nadine Novak Opinions expressed are solely my own and not those of Public Access Unix of New York. ------------------------------------------------------------