From llindqvist@illinois.edu Fri Jun 23 04:00:10 1995 Path: ashpoly!cascade!brgate!saturno!illinois!llindqvist From: llindqvist@illinois.edu (Lucia Lindqvist) Newsgroups: comp.dsp Subject: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jun23.040010.5447@illinois.edu> Date: Fri, 23 Jun 1995 04:00:10 GMT Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: WinVN 0.99.5 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. -- Lucia Lindqvist -- University of Illinois Urbana-Champaign "When every node is whole, the channel opens." From mweber@panix.com Sat Jun 24 07:26:10 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!panix!mweber From: mweber@panix.com (Mike Weber) Newsgroups: comp.dsp Subject: Re: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jun24.072610.6957@panix.com> Date: Sat, 24 Jun 1995 07:26:10 GMT References: <1995Jun23.040010.5447@illinois.edu> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1995Jun23.040010.5447@illinois.edu>, llindqvist@illinois.edu (Lucia Lindqvist) writes: > 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. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. If you are posting from AOL, please read RFC 1036 before posting again. -- Mike Weber Tape trading list upon request. SASE required for international mail. From lweber@earthlink.net Sun Jun 25 04:04:10 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!earthlink!lweber From: lweber@earthlink.net (Lars Weber) Newsgroups: comp.dsp Subject: Re: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jun25.040410.2136@earthlink.net> Date: Sun, 25 Jun 1995 04:04:10 GMT References: <1995Jun23.040010.5447@illinois.edu> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Jun23.040010.5447@illinois.edu>, llindqvist@illinois.edu (Lucia Lindqvist) 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! Top-posters will be placed in my ~/.killfile without notice. -- Lars Weber Tape trading list upon request. SASE required for international mail. From tfournier@mit.edu Tue Jun 27 05:51:10 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!mit!tfournier From: tfournier@mit.edu (Thiago Fournier) Newsgroups: comp.dsp Subject: Re: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jun27.055110.3543@mit.edu> Date: Tue, 27 Jun 1995 05:51:10 GMT References: <1995Jun23.040010.5447@illinois.edu> <1995Jun24.072610.6957@panix.com> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Jun24.072610.6957@panix.com>, mweber@panix.com (Mike Weber) writes: > Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. > If you are posting from AOL, please read RFC 1036 before posting again. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Thiago Fournier "They will send a copy in my place." Atari TT030 / System 7.5.1 From mfischer@earthlink.net Tue Jun 27 14:21:10 1995 Path: ashpoly!cascade!brgate!saturno!earthlink!mfischer From: mfischer@earthlink.net (Mikhail Fischer) Newsgroups: comp.dsp Subject: Re: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jun27.142110.9578@earthlink.net> Date: Tue, 27 Jun 1995 14:21:10 GMT References: <1995Jun23.040010.5447@illinois.edu> <1995Jun25.040410.2136@earthlink.net> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Jun25.040410.2136@earthlink.net>, lweber@earthlink.net (Lars Weber) writes: > Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit! > Top-posters will be placed in my ~/.killfile without notice. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Mikhail Fischer "We don't sign stars. We build them." Decstation 5000/200 / TOS 4.04