From ystewart@cam.ac.uk Wed Feb 28 15:52:05 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!cam!ystewart From: ystewart@cam.ac.uk (Yuki Stewart) Newsgroups: comp.dsp Subject: Observation: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Feb28.155205.7058@cam.ac.uk> Date: Wed, 28 Feb 1996 15:52:05 GMT Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 10 Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop. 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. -- Yuki Stewart Tape trading list upon request. SASE required for international mail. From enakamura@mindspring.com Fri Mar 01 01:08:05 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!mindspring!enakamura From: enakamura@mindspring.com (Emi Nakamura) Newsgroups: comp.dsp Subject: Re: Observation: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Mar01.010805.2760@mindspring.com> Date: Fri, 01 Mar 1996 01:08:05 GMT References: <1996Feb28.155205.7058@cam.ac.uk> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1996Feb28.155205.7058@cam.ac.uk>, ystewart@cam.ac.uk (Yuki Stewart) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. > However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Emi Nakamura Practical Peripherals 14.4 @ 14,400 bps "5 sigma is a discovery. 7 is a question." From gpopov@purdue.edu Sat Mar 02 22:57:05 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!purdue!gpopov From: gpopov@purdue.edu (Göran Popov) Newsgroups: comp.dsp Subject: Re: Observation: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Mar02.225705.6677@purdue.edu> Date: Sat, 02 Mar 1996 22:57:05 GMT References: <1996Feb28.155205.7058@cam.ac.uk> Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1996Feb28.155205.7058@cam.ac.uk>, ystewart@cam.ac.uk (Yuki Stewart) 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. -- Göran Popov Opinions expressed are solely my own and not those of Purdue University Engineering Computer Network. ------------------------------------------------------------ From msato@titech.ac.jp Mon Mar 04 10:37:05 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!titech!msato From: msato@titech.ac.jp (Mike Sato) Newsgroups: comp.dsp Subject: Re: Observation: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Mar04.103705.3697@titech.ac.jp> Date: Mon, 04 Mar 1996 10:37:05 GMT References: <1996Feb28.155205.7058@cam.ac.uk> <1996Mar02.225705.6677@purdue.edu> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1996Mar02.225705.6677@purdue.edu>, gpopov@purdue.edu (Göran Popov) 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. PGP Public key available via finger or upon request. -- Mike Sato Tape trading list upon request. SASE required for international mail.