From mmartinez@inria.fr Sun Jul 16 06:08:24 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!inria!mmartinez From: mmartinez@inria.fr (Mei Martínez) Newsgroups: comp.dsp Subject: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jul16.060824.9526@inria.fr> Date: Sun, 16 Jul 1995 06:08:24 GMT Organization: INRIA Rocquencourt NNTP-Posting-Host: inria.fr X-Newsreader: TIN [version 1.2 PL2] Lines: 11 Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. 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. Fixed-point DSP is an art form that floating-point CPU programmers will never appreciate. -- Mei Martínez *PLONK* filter active for trolls. Macintosh IIfx - NetBSD 1.0 From jmoreno@earthlink.net Mon Jul 17 15:18:24 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!earthlink!jmoreno From: jmoreno@earthlink.net (Ji-woo Moreno) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jul17.151824.5764@earthlink.net> Date: Mon, 17 Jul 1995 15:18:24 GMT References: <1995Jul16.060824.9526@inria.fr> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Jul16.060824.9526@inria.fr>, mmartinez@inria.fr (Mei Martínez) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. > 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. -- Ji-woo Moreno | jmoreno@earthlink.net PGP Key fingerprint: 3AC3 167A BF86 3628 "Keep the channels open." From vmoreno@kth.se Tue Jul 18 12:39:24 1995 Path: ashpoly!cascade!bigsur!kth!vmoreno From: vmoreno@kth.se (Valeria Moreno) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jul18.123924.7040@kth.se> Date: Tue, 18 Jul 1995 12:39:24 GMT References: <1995Jul16.060824.9526@inria.fr> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Jul16.060824.9526@inria.fr>, mmartinez@inria.fr (Mei Martínez) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit! -- Valeria Moreno "5 sigma is a discovery. 7 is a question." Amiga 1200 (Blizzard 030/50) / System 7.5.1 From afischer@unam.mx Wed Jul 19 08:53:24 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!unam!afischer From: afischer@unam.mx (Anton Fischer) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jul19.085324.3463@unam.mx> Date: Wed, 19 Jul 1995 08:53:24 GMT References: <1995Jul16.060824.9526@inria.fr> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1995Jul16.060824.9526@inria.fr>, mmartinez@inria.fr (Mei Martínez) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns. -- Anton Fischer | afischer@unam.mx PGP Key fingerprint: 986E 3FCF D08E F2E4 "Keep the channels open." From klindqvist@illinois.edu Wed Jul 19 10:35:24 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!illinois!klindqvist From: klindqvist@illinois.edu (Kenji Lindqvist) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jul19.103524.6208@illinois.edu> Date: Wed, 19 Jul 1995 10:35:24 GMT References: <1995Jul16.060824.9526@inria.fr> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Jul16.060824.9526@inria.fr>, mmartinez@inria.fr (Mei Martínez) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. > 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. -- Kenji Lindqvist Hayes Optima 288 @ 14,400 bps "Hold for relay."