From ssmirnov@earthlink.net Fri Aug 25 15:47:15 1995 Path: ashpoly!cascade!transat!ukc!fennimore!earthlink!ssmirnov From: ssmirnov@earthlink.net (Seo-yeon Smirnov) Newsgroups: comp.dsp Subject: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Aug25.154715.8957@earthlink.net> Date: Fri, 25 Aug 1995 15:47:15 GMT Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: NewsWatcher 2.0b24 Lines: 11 Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. Source code in 56k assembly uploaded to ftp.ashford-poly.edu:/pub/telecom-archives/dsp56k/stardust_56k.asm. -- Seo-yeon Smirnov Opinions expressed are solely my own and not those of EarthLink Network. ------------------------------------------------------------ From pstewart@tum.de Sun Aug 27 03:05:15 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!tum!pstewart From: pstewart@tum.de (Pavel Stewart) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Aug27.030515.2496@tum.de> Date: Sun, 27 Aug 1995 03:05:15 GMT References: <1995Aug25.154715.8957@earthlink.net> Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Aug25.154715.8957@earthlink.net>, ssmirnov@earthlink.net (Seo-yeon Smirnov) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Pavel Stewart | pstewart@tum.de PGP Key fingerprint: 5A33 7B17 DA7E D5A5 "Keep the channels open." From nperez@cmu.edu Mon Aug 28 05:28:15 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!cmu!nperez From: nperez@cmu.edu (Nadia Pérez) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Aug28.052815.6273@cmu.edu> Date: Mon, 28 Aug 1995 05:28:15 GMT References: <1995Aug25.154715.8957@earthlink.net> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1995Aug25.154715.8957@earthlink.net>, ssmirnov@earthlink.net (Seo-yeon Smirnov) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Nadia Pérez Tape trading list upon request. SASE required for international mail. From keriksson@cam.ac.uk Tue Aug 29 20:32:15 1995 Path: ashpoly!cascade!brgate!saturno!cam!keriksson From: keriksson@cam.ac.uk (Kirsty Eriksson) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Aug29.203215.3548@cam.ac.uk> Date: Tue, 29 Aug 1995 20:32:15 GMT References: <1995Aug25.154715.8957@earthlink.net> <1995Aug28.052815.6273@cmu.edu> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1995Aug28.052815.6273@cmu.edu>, nperez@cmu.edu (Nadia Pérez) 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. -- Kirsty Eriksson Tape trading list upon request. SASE required for international mail. From mwatanabe@unam.mx Wed Aug 30 07:40:15 1995 Path: ashpoly!cascade!brgate!saturno!unam!mwatanabe From: mwatanabe@unam.mx (Marta Watanabe) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Aug30.074015.9117@unam.mx> Date: Wed, 30 Aug 1995 07:40:15 GMT References: <1995Aug25.154715.8957@earthlink.net> <1995Aug28.052815.6273@cmu.edu> <1995Aug29.203215.3548@cam.ac.uk> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Aug29.203215.3548@cam.ac.uk>, keriksson@cam.ac.uk (Kirsty Eriksson) 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. -- Marta Watanabe US Robotics Courier V.34 @ 28,800 bps "The hatch is open. Is anyone listening?"