From llaurent@uu.net Tue Apr 11 06:51:16 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!uu!llaurent From: llaurent@uu.net (Lisa Laurent) Newsgroups: comp.dsp Subject: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr11.065116.8508@uu.net> Date: Tue, 11 Apr 1995 06:51:16 GMT Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net 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. -- Lisa Laurent | llaurent@uu.net PGP Key fingerprint: C271 896B 083F DF09 "Keep the channels open." From btakahashi@hanse.de Tue Apr 11 22:40:16 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!hanse!btakahashi From: btakahashi@hanse.de (Bastien Takahashi) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr11.224016.2261@hanse.de> Date: Tue, 11 Apr 1995 22:40:16 GMT References: <1995Apr11.065116.8508@uu.net> Organization: Hanse-Netzwerk Hamburg NNTP-Posting-Host: hanse.de X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1995Apr11.065116.8508@uu.net>, llaurent@uu.net (Lisa Laurent) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Top-posters will be placed in my ~/.killfile without notice. -- Bastien Takahashi *PLONK* filter active for trolls. Atari Falcon 030 - NetBSD 1.0 From vlee@titech.ac.jp Thu Apr 13 04:41:16 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!titech!vlee From: vlee@titech.ac.jp (Valeria Lee) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr13.044116.4847@titech.ac.jp> Date: Thu, 13 Apr 1995 04:41:16 GMT References: <1995Apr11.065116.8508@uu.net> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Apr11.065116.8508@uu.net>, llaurent@uu.net (Lisa Laurent) 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. -- Valeria Lee Opinions expressed are solely my own and not those of Tokyo Institute of Technology Computer Centre. ------------------------------------------------------------ From bduarte@clari.net Fri Apr 14 00:36:16 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!clari!bduarte From: bduarte@clari.net (Bastien Duarte) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr14.003616.5568@clari.net> Date: Fri, 14 Apr 1995 00:36:16 GMT References: <1995Apr11.065116.8508@uu.net> <1995Apr13.044116.4847@titech.ac.jp> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Apr13.044116.4847@titech.ac.jp>, vlee@titech.ac.jp (Valeria Lee) 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. -- Bastien Duarte | bduarte@clari.net PGP Key fingerprint: 73E0 E830 4CD1 9522 "Keep the channels open."