From snilsson@ox.ac.uk Thu Jan 05 10:16:04 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!ox!snilsson From: snilsson@ox.ac.uk (Sven Nilsson) Newsgroups: comp.dsp Subject: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jan05.101604.6741@ox.ac.uk> Date: Thu, 05 Jan 1995 10:16:04 GMT Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: WinVN 0.99.5 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. -- === Sven Nilsson === Dept of Electrical Engineering, Oxford University Computing Laboratory "When every node is whole, the channel opens." From lreyes@inria.fr Sat Jan 07 08:12:04 1995 Path: ashpoly!cascade!mxgate!coyoacan!inria!lreyes From: lreyes@inria.fr (Lisa Reyes) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jan07.081204.9218@inria.fr> Date: Sat, 07 Jan 1995 08:12:04 GMT References: <1995Jan05.101604.6741@ox.ac.uk> Organization: INRIA Rocquencourt NNTP-Posting-Host: inria.fr X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Jan05.101604.6741@ox.ac.uk>, snilsson@ox.ac.uk (Sven Nilsson) 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. -- Lisa Reyes | lreyes@inria.fr PGP Key fingerprint: C67A 7240 EB26 EC85 "Keep the channels open." From bjohansson@cmu.edu Mon Jan 09 04:53:04 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!cmu!bjohansson From: bjohansson@cmu.edu (Brian Johansson) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jan09.045304.8412@cmu.edu> Date: Mon, 09 Jan 1995 04:53:04 GMT References: <1995Jan05.101604.6741@ox.ac.uk> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Jan05.101604.6741@ox.ac.uk>, snilsson@ox.ac.uk (Sven Nilsson) 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. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Brian Johansson Opinions expressed are solely my own and not those of Carnegie Mellon University School of CS. ------------------------------------------------------------ From jpopov@illinois.edu Mon Jan 09 07:04:04 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!illinois!jpopov From: jpopov@illinois.edu (Ji-woo Popov) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jan09.070404.5134@illinois.edu> Date: Mon, 09 Jan 1995 07:04:04 GMT References: <1995Jan05.101604.6741@ox.ac.uk> <1995Jan07.081204.9218@inria.fr> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Jan07.081204.9218@inria.fr>, lreyes@inria.fr (Lisa Reyes) writes: > Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Ji-woo Popov | jpopov@illinois.edu PGP Key fingerprint: 823E 57F6 DE4F 365F "Keep the channels open." From asokolov@uu.net Tue Jan 10 19:49:04 1995 Path: ashpoly!cascade!brgate!saturno!uu!asokolov From: asokolov@uu.net (Amy Sokolov) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jan10.194904.6606@uu.net> Date: Tue, 10 Jan 1995 19:49:04 GMT References: <1995Jan05.101604.6741@ox.ac.uk> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Jan05.101604.6741@ox.ac.uk>, snilsson@ox.ac.uk (Sven Nilsson) 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. -- Amy Sokolov Opinions expressed are solely my own and not those of UUNET Technologies, Falls Church VA. ------------------------------------------------------------