From mgonzalez@u-tokyo.ac.jp Sun Aug 04 17:49:24 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!u-tokyo!mgonzalez From: mgonzalez@u-tokyo.ac.jp (Mike González) Newsgroups: comp.dsp Subject: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Aug04.174924.2968@u-tokyo.ac.jp> Date: Sun, 04 Aug 1996 17:49:24 GMT Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: Netscape 1.1N Lines: 11 Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. Source code in 56k assembly uploaded to ftp.ashford-poly.edu:/pub/telecom-archives/dsp56k/stardust_56k.asm. -- Mike González Opinions expressed are solely my own and not those of University of Tokyo Department of Information Science. ------------------------------------------------------------ From thernandez@u-tokyo.ac.jp Mon Aug 05 09:29:24 1996 Path: ashpoly!cascade!bigsur!u-tokyo!thernandez From: thernandez@u-tokyo.ac.jp (Tobias Hernández) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Aug05.092924.5579@u-tokyo.ac.jp> Date: Mon, 05 Aug 1996 09:29:24 GMT References: <1996Aug04.174924.2968@u-tokyo.ac.jp> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1996Aug04.174924.2968@u-tokyo.ac.jp>, mgonzalez@u-tokyo.ac.jp (Mike González) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. > This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Tobias Hernández Hayes Optima 288 @ 19,200 bps "Hold for relay." From olee@clari.net Wed Aug 07 02:34:24 1996 Path: ashpoly!cascade!brgate!saturno!clari!olee From: olee@clari.net (Olga Lee) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Aug07.023424.8322@clari.net> Date: Wed, 07 Aug 1996 02:34:24 GMT References: <1996Aug04.174924.2968@u-tokyo.ac.jp> <1996Aug05.092924.5579@u-tokyo.ac.jp> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1996Aug05.092924.5579@u-tokyo.ac.jp>, thernandez@u-tokyo.ac.jp (Tobias Hernández) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Olga Lee -- ClariNet Communications Corp "The hatch is open. Is anyone listening?" From jtakahashi@unam.mx Thu Aug 08 16:01:24 1996 Path: ashpoly!cascade!transat!sunet!nordrelay!unam!jtakahashi From: jtakahashi@unam.mx (Jens Takahashi) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Aug08.160124.4080@unam.mx> Date: Thu, 08 Aug 1996 16:01:24 GMT References: <1996Aug04.174924.2968@u-tokyo.ac.jp> <1996Aug05.092924.5579@u-tokyo.ac.jp> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1996Aug05.092924.5579@u-tokyo.ac.jp>, thernandez@u-tokyo.ac.jp (Tobias Hernández) 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. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Jens Takahashi | jtakahashi@unam.mx PGP Key fingerprint: F098 B1A5 8393 8F2B "Keep the channels open."