From ahughes@mit.edu Wed Oct 11 20:32:37 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!mit!ahughes From: ahughes@mit.edu (Andrei Hughes) Newsgroups: comp.dsp Subject: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct11.203237.9664@mit.edu> Date: Wed, 11 Oct 1995 20:32:37 GMT Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: Netscape 1.1N Lines: 11 Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. 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. -- Andrei Hughes "A soul is not exclusive to biology." Mac IIci / 68882 FPU / SunOS 4.1.4 From fsuzuki@illinois.edu Fri Oct 13 03:00:37 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!illinois!fsuzuki From: fsuzuki@illinois.edu (Freya Suzuki) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct13.030037.2652@illinois.edu> Date: Fri, 13 Oct 1995 03:00:37 GMT References: <1995Oct11.203237.9664@mit.edu> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 12 In article <1995Oct11.203237.9664@mit.edu>, ahughes@mit.edu (Andrei Hughes) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. > The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Top-posters will be placed in my ~/.killfile without notice. -- Freya Suzuki "5 sigma is a discovery. 7 is a question." Acorn RiscPC 600 / TOS 4.04 From mstewart@clari.net Sun Oct 15 02:46:37 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!clari!mstewart From: mstewart@clari.net (Marta Stewart) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct15.024637.7761@clari.net> Date: Sun, 15 Oct 1995 02:46:37 GMT References: <1995Oct11.203237.9664@mit.edu> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Oct11.203237.9664@mit.edu>, ahughes@mit.edu (Andrei Hughes) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. > The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Marta Stewart Opinions expressed are solely my own and not those of ClariNet Communications Corp. ------------------------------------------------------------