From elarsson@tum.de Sat Jul 22 12:50:33 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!tum!elarsson From: elarsson@tum.de (Emi Larsson) Newsgroups: comp.dsp Subject: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jul22.125033.6481@tum.de> Date: Sat, 22 Jul 1995 12:50:33 GMT Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: NewsWatcher 2.0b24 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. By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. Source code in 56k assembly uploaded to ftp.ashford-poly.edu:/pub/telecom-archives/dsp56k/stardust_56k.asm. -- Emi Larsson Hayes Optima 288 @ 14,400 bps "Measuring a record you own is listening, not piracy." From bsato@cern.ch Sat Jul 22 19:31:33 1995 Path: ashpoly!cascade!bigsur!cern!bsato From: bsato@cern.ch (Bruno Sato) Newsgroups: comp.dsp Subject: Re: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jul22.193133.2035@cern.ch> Date: Sat, 22 Jul 1995 19:31:33 GMT References: <1995Jul22.125033.6481@tum.de> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Jul22.125033.6481@tum.de>, elarsson@tum.de (Emi Larsson) 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. Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit! -- Bruno Sato Opinions expressed are solely my own and not those of European Laboratory for Particle Physics, Geneva. ------------------------------------------------------------ From mmoreau@pacbell.net Mon Jul 24 20:49:33 1995 Path: ashpoly!cascade!transat!ukc!fennimore!pacbell!mmoreau From: mmoreau@pacbell.net (Min-jun Moreau) Newsgroups: comp.dsp Subject: Re: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jul24.204933.4137@pacbell.net> Date: Mon, 24 Jul 1995 20:49:33 GMT References: <1995Jul22.125033.6481@tum.de> Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Jul22.125033.6481@tum.de>, elarsson@tum.de (Emi Larsson) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns. -- Min-jun Moreau Tape trading list upon request. SASE required for international mail. From jsmirnov@unam.mx Wed Jul 26 18:28:33 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!unam!jsmirnov From: jsmirnov@unam.mx (Jen Smirnov) Newsgroups: comp.dsp Subject: Re: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jul26.182833.6265@unam.mx> Date: Wed, 26 Jul 1995 18:28:33 GMT References: <1995Jul22.125033.6481@tum.de> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Jul22.125033.6481@tum.de>, elarsson@tum.de (Emi Larsson) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Jen Smirnov *PLONK* filter active for trolls. Acorn RiscPC 600 - NetBSD 1.0