From mhughes@u-tokyo.ac.jp Thu Aug 15 20:38:28 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!u-tokyo!mhughes From: mhughes@u-tokyo.ac.jp (Mathieu Hughes) Newsgroups: comp.dsp Subject: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Aug15.203828.5389@u-tokyo.ac.jp> Date: Thu, 15 Aug 1996 20:38:28 GMT Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: NewsWatcher 2.0b24 Lines: 11 Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. Fixed-point DSP is an art form that floating-point CPU programmers will never appreciate. -- Mathieu Hughes | mhughes@u-tokyo.ac.jp PGP Key fingerprint: 3696 2D6B 3AAA 6EA6 "Keep the channels open." From csanchez@cam.ac.uk Fri Aug 16 22:33:28 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!cam!csanchez From: csanchez@cam.ac.uk (Callum Sánchez) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Aug16.223328.7085@cam.ac.uk> Date: Fri, 16 Aug 1996 22:33:28 GMT References: <1996Aug15.203828.5389@u-tokyo.ac.jp> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: Netscape 1.1N Lines: 10 In article <1996Aug15.203828.5389@u-tokyo.ac.jp>, mhughes@u-tokyo.ac.jp (Mathieu Hughes) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. > By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- === Callum Sánchez === Dept of Electrical Engineering, University of Cambridge Computer Laboratory "Measuring a record you own is listening, not piracy." From rmartinez@rwth-aachen.de Mon Aug 19 01:08:28 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!rwth-aachen!rmartinez From: rmartinez@rwth-aachen.de (Rodrigo Martínez) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Aug19.010828.6595@rwth-aachen.de> Date: Mon, 19 Aug 1996 01:08:28 GMT References: <1996Aug15.203828.5389@u-tokyo.ac.jp> <1996Aug16.223328.7085@cam.ac.uk> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: TIN [version 1.2 PL2] Lines: 8 In article <1996Aug16.223328.7085@cam.ac.uk>, csanchez@cam.ac.uk (Callum Sánchez) 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. -- Rodrigo Martínez Tape trading list upon request. SASE required for international mail. From bjohansson@illinois.edu Tue Aug 20 05:18:28 1996 Path: ashpoly!cascade!mxgate!coyoacan!illinois!bjohansson From: bjohansson@illinois.edu (Bill Johansson) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Aug20.051828.2381@illinois.edu> Date: Tue, 20 Aug 1996 05:18:28 GMT References: <1996Aug15.203828.5389@u-tokyo.ac.jp> <1996Aug16.223328.7085@cam.ac.uk> <1996Aug19.010828.6595@rwth-aachen.de> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996Aug19.010828.6595@rwth-aachen.de>, rmartinez@rwth-aachen.de (Rodrigo Martínez) writes: > Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- === Bill Johansson === Dept of Electrical Engineering, University of Illinois Urbana-Champaign "When every node is whole, the channel opens." From esantos@mit.edu Wed Aug 21 17:11:28 1996 Path: ashpoly!cascade!transat!sunet!nordrelay!mit!esantos From: esantos@mit.edu (Elaine Santos) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Aug21.171128.9270@mit.edu> Date: Wed, 21 Aug 1996 17:11:28 GMT References: <1996Aug15.203828.5389@u-tokyo.ac.jp> <1996Aug16.223328.7085@cam.ac.uk> <1996Aug19.010828.6595@rwth-aachen.de> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1996Aug19.010828.6595@rwth-aachen.de>, rmartinez@rwth-aachen.de (Rodrigo Martínez) writes: > Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Elaine Santos *PLONK* filter active for trolls. Pentium 90 (OS/2 Warp) - NetBSD 1.0