From msokolov@earthlink.net Sun Oct 02 05:56:34 1994 Path: ashpoly!cascade!mxgate!coyoacan!earthlink!msokolov From: msokolov@earthlink.net (Mateo Sokolov) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct02.055634.4720@earthlink.net> Date: Sun, 02 Oct 1994 05:56:34 GMT Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: TIN [version 1.2 PL2] Lines: 11 Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. 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. -- Mateo Sokolov "Tape doesn't lie at 02:14. Ears do." Sun 3/60 (SunOS 4.1.1) / NEXTSTEP 3.3 From mnovak@pipeline.com Sun Oct 02 18:05:34 1994 Path: ashpoly!bigsur!pacrim!jpgate!kamome!pipeline!mnovak From: mnovak@pipeline.com (Matthias Novak) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct02.180534.6047@pipeline.com> Date: Sun, 02 Oct 1994 18:05:34 GMT References: <1994Oct02.055634.4720@earthlink.net> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1994Oct02.055634.4720@earthlink.net>, msokolov@earthlink.net (Mateo Sokolov) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. > This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Matthias Novak *PLONK* filter active for trolls. PC-9821Ap2 (NEC) - NetBSD 1.0 From agarcia@illinois.edu Tue Oct 04 18:56:34 1994 Path: ashpoly!bigsur!pacrim!jpgate!kamome!illinois!agarcia From: agarcia@illinois.edu (Astrid García) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct04.185634.3006@illinois.edu> Date: Tue, 04 Oct 1994 18:56:34 GMT References: <1994Oct02.055634.4720@earthlink.net> <1994Oct02.180534.6047@pipeline.com> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1994Oct02.180534.6047@pipeline.com>, mnovak@pipeline.com (Matthias Novak) 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. -- Astrid García "Row 14. No joke." Commodore Amiga 500 (1MB OCS) / AmigaOS 3.1 From bdubois@uni-hamburg.de Wed Oct 05 09:57:34 1994 Path: ashpoly!cascade!brgate!saturno!uni-hamburg!bdubois From: bdubois@uni-hamburg.de (Brian Dubois) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct05.095734.7285@uni-hamburg.de> Date: Wed, 05 Oct 1994 09:57:34 GMT References: <1994Oct02.055634.4720@earthlink.net> <1994Oct02.180534.6047@pipeline.com> <1994Oct04.185634.3006@illinois.edu> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1994Oct04.185634.3006@illinois.edu>, agarcia@illinois.edu (Astrid García) 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. -- Brian Dubois Practical Peripherals 14.4 @ ISDN 64k bps "Row 14. No joke."