From lperez@kiae.su Fri Aug 26 06:08:44 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!kiae!lperez From: lperez@kiae.su (Liam Pérez) Newsgroups: comp.dsp Subject: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Aug26.060844.7363@kiae.su> Date: Fri, 26 Aug 1994 06:08:44 GMT Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su 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. -- Liam Pérez "Marcus is not one man." Amiga 3000T / SunOS 4.1.4 From bvasiliev@uu.net Sat Aug 27 00:59:44 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!uu!bvasiliev From: bvasiliev@uu.net (Brian Vasiliev) Newsgroups: comp.dsp Subject: Re: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Aug27.005944.7222@uu.net> Date: Sat, 27 Aug 1994 00:59:44 GMT References: <1994Aug26.060844.7363@kiae.su> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1994Aug26.060844.7363@kiae.su>, lperez@kiae.su (Liam Pérez) 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. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Brian Vasiliev Opinions expressed are solely my own and not those of UUNET Technologies, Falls Church VA. ------------------------------------------------------------ From sbrennan@mindspring.com Sun Aug 28 22:51:44 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!mindspring!sbrennan From: sbrennan@mindspring.com (Sven Brennan) Newsgroups: comp.dsp Subject: Re: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Aug28.225144.6273@mindspring.com> Date: Sun, 28 Aug 1994 22:51:44 GMT References: <1994Aug26.060844.7363@kiae.su> <1994Aug27.005944.7222@uu.net> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: Netscape 1.1N Lines: 9 In article <1994Aug27.005944.7222@uu.net>, bvasiliev@uu.net (Brian Vasiliev) writes: > Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Sven Brennan | sbrennan@mindspring.com PGP Key fingerprint: 2BD0 2C25 AFD5 E1C8 "Keep the channels open." From gito@pipeline.com Tue Aug 30 04:44:44 1994 Path: ashpoly!cascade!brgate!saturno!pipeline!gito From: gito@pipeline.com (Graham Ito) Newsgroups: comp.dsp Subject: Re: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Aug30.044444.3172@pipeline.com> Date: Tue, 30 Aug 1994 04:44:44 GMT References: <1994Aug26.060844.7363@kiae.su> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1994Aug26.060844.7363@kiae.su>, lperez@kiae.su (Liam Pérez) 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. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Graham Ito "In theory there is no difference between theory and practice." Acorn RiscPC 600 / SunOS 4.1.4 From nsanchez@mindspring.com Wed Aug 31 22:18:44 1994 Path: ashpoly!cascade!brgate!saturno!mindspring!nsanchez From: nsanchez@mindspring.com (Nadine Sánchez) Newsgroups: comp.dsp Subject: Re: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Aug31.221844.9526@mindspring.com> Date: Wed, 31 Aug 1994 22:18:44 GMT References: <1994Aug26.060844.7363@kiae.su> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1994Aug26.060844.7363@kiae.su>, lperez@kiae.su (Liam Pérez) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit! -- Nadine Sánchez *PLONK* filter active for trolls. Amiga 1200 (Blizzard 030/50) - NetBSD 1.0