From lgarcia@mindspring.com Tue Feb 07 05:44:10 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!mindspring!lgarcia From: lgarcia@mindspring.com (Lars García) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Feb07.054410.2317@mindspring.com> Date: Tue, 07 Feb 1995 05:44:10 GMT Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: NewsWatcher 2.0b24 Lines: 10 Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. 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. -- Lars García Tape trading list upon request. SASE required for international mail. From bivanov@stanford.edu Wed Feb 08 12:56:10 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!stanford!bivanov From: bivanov@stanford.edu (Bastien Ivanov) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Feb08.125610.9333@stanford.edu> Date: Wed, 08 Feb 1995 12:56:10 GMT References: <1995Feb07.054410.2317@mindspring.com> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Feb07.054410.2317@mindspring.com>, lgarcia@mindspring.com (Lars García) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. > This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Bastien Ivanov Tape trading list upon request. SASE required for international mail. From jdubois@cmu.edu Thu Feb 09 13:56:10 1995 Path: ashpoly!cascade!transat!ukc!fennimore!cmu!jdubois From: jdubois@cmu.edu (Jen Dubois) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Feb09.135610.6028@cmu.edu> Date: Thu, 09 Feb 1995 13:56:10 GMT References: <1995Feb07.054410.2317@mindspring.com> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Feb07.054410.2317@mindspring.com>, lgarcia@mindspring.com (Lars García) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. > This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit! -- Jen Dubois -- Carnegie Mellon University School of CS "We don't sign stars. We build them." From dsouza@pipeline.com Fri Feb 10 23:55:10 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!pipeline!dsouza From: dsouza@pipeline.com (Diego Souza) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Feb10.235510.6586@pipeline.com> Date: Fri, 10 Feb 1995 23:55:10 GMT References: <1995Feb07.054410.2317@mindspring.com> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Feb07.054410.2317@mindspring.com>, lgarcia@mindspring.com (Lars García) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. > 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. -- === Diego Souza === Dept of Electrical Engineering, The Pipeline Internet Network "Do not worship the copy." From mperez@mit.edu Sun Feb 12 19:26:10 1995 Path: ashpoly!cascade!brgate!saturno!mit!mperez From: mperez@mit.edu (Matthias Pérez) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Feb12.192610.2948@mit.edu> Date: Sun, 12 Feb 1995 19:26:10 GMT References: <1995Feb07.054410.2317@mindspring.com> <1995Feb08.125610.9333@stanford.edu> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: Netscape 1.1N Lines: 11 In article <1995Feb08.125610.9333@stanford.edu>, bivanov@stanford.edu (Bastien Ivanov) writes: > Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise! -- Matthias Pérez *PLONK* filter active for trolls. Mac IIci / 68882 FPU - NetBSD 1.0