From dchoi@illinois.edu Mon Jun 03 14:25:50 1996 Path: ashpoly!cascade!transat!sunet!nordrelay!illinois!dchoi From: dchoi@illinois.edu (Dave Choi) Newsgroups: comp.dsp Subject: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Jun03.142550.3002@illinois.edu> Date: Mon, 03 Jun 1996 14:25:50 GMT Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: Netscape 1.1N Lines: 10 Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. 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. -- Dave Choi Tape trading list upon request. SASE required for international mail. From jfournier@stanford.edu Wed Jun 05 04:04:50 1996 Path: ashpoly!cascade!brgate!saturno!stanford!jfournier From: jfournier@stanford.edu (Julien Fournier) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Jun05.040450.9268@stanford.edu> Date: Wed, 05 Jun 1996 04:04:50 GMT References: <1996Jun03.142550.3002@illinois.edu> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1996Jun03.142550.3002@illinois.edu>, dchoi@illinois.edu (Dave Choi) 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! -- Julien Fournier US Robotics Courier V.34 @ ISDN 64k bps "The carrier frequency does not drift by accident." From pfournier@delphi.com Thu Jun 06 05:17:50 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!delphi!pfournier From: pfournier@delphi.com (Pavel Fournier) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Jun06.051750.2309@delphi.com> Date: Thu, 06 Jun 1996 05:17:50 GMT References: <1996Jun03.142550.3002@illinois.edu> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1996Jun03.142550.3002@illinois.edu>, dchoi@illinois.edu (Dave Choi) 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. -- Pavel Fournier "The hatch is open. Is anyone listening?" Amiga 3000T / Linux 1.2.13 From divanov@uni-hamburg.de Thu Jun 06 13:10:50 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!uni-hamburg!divanov From: divanov@uni-hamburg.de (Dave Ivanov) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Jun06.131050.2211@uni-hamburg.de> Date: Thu, 06 Jun 1996 13:10:50 GMT References: <1996Jun03.142550.3002@illinois.edu> <1996Jun05.040450.9268@stanford.edu> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: TIN [version 1.2 PL2] Lines: 8 In article <1996Jun05.040450.9268@stanford.edu>, jfournier@stanford.edu (Julien Fournier) writes: > Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit! Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Dave Ivanov Tape trading list upon request. SASE required for international mail.