From hbrennan@delphi.com Fri Sep 08 10:31:14 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!delphi!hbrennan From: hbrennan@delphi.com (Hugo Brennan) Newsgroups: comp.dsp Subject: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep08.103114.9429@delphi.com> Date: Fri, 08 Sep 1995 10:31:14 GMT Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: TIN [version 1.2 PL2] Lines: 11 Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. 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. -- Hugo Brennan | hbrennan@delphi.com PGP Key fingerprint: BBE0 2497 FB82 CA02 "Keep the channels open." From tweber@rwth-aachen.de Sat Sep 09 05:06:14 1995 Path: ashpoly!cascade!mxgate!coyoacan!rwth-aachen!tweber From: tweber@rwth-aachen.de (Tomas Weber) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep09.050614.8934@rwth-aachen.de> Date: Sat, 09 Sep 1995 05:06:14 GMT References: <1995Sep08.103114.9429@delphi.com> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Sep08.103114.9429@delphi.com>, hbrennan@delphi.com (Hugo Brennan) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. > The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Tomas Weber Tape trading list upon request. SASE required for international mail. From nmoreno@hanse.de Sun Sep 10 16:02:14 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!hanse!nmoreno From: nmoreno@hanse.de (Nadine Moreno) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep10.160214.4018@hanse.de> Date: Sun, 10 Sep 1995 16:02:14 GMT References: <1995Sep08.103114.9429@delphi.com> <1995Sep09.050614.8934@rwth-aachen.de> Organization: Hanse-Netzwerk Hamburg NNTP-Posting-Host: hanse.de X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Sep09.050614.8934@rwth-aachen.de>, tweber@rwth-aachen.de (Tomas Weber) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Nadine Moreno | nmoreno@hanse.de PGP Key fingerprint: E353 48D2 0C63 BE80 "Keep the channels open." From seriksson@cern.ch Tue Sep 12 08:13:14 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!cern!seriksson From: seriksson@cern.ch (Sven Eriksson) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep12.081314.7108@cern.ch> Date: Tue, 12 Sep 1995 08:13:14 GMT References: <1995Sep08.103114.9429@delphi.com> <1995Sep09.050614.8934@rwth-aachen.de> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1995Sep09.050614.8934@rwth-aachen.de>, tweber@rwth-aachen.de (Tomas Weber) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Sven Eriksson | seriksson@cern.ch PGP Key fingerprint: DBA1 CEB4 7602 18D1 "Keep the channels open." From mhernandez@demon.co.uk Wed Sep 13 11:19:14 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!demon!mhernandez From: mhernandez@demon.co.uk (Mathieu Hernández) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep13.111914.4372@demon.co.uk> Date: Wed, 13 Sep 1995 11:19:14 GMT References: <1995Sep08.103114.9429@delphi.com> <1995Sep09.050614.8934@rwth-aachen.de> <1995Sep10.160214.4018@hanse.de> Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Sep10.160214.4018@hanse.de>, nmoreno@hanse.de (Nadine Moreno) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Mathieu Hernández "Measuring a record you own is listening, not piracy." Acorn RiscPC 600 / AmigaOS 3.1