From clindqvist@earthlink.net Sun Dec 18 12:32:52 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!earthlink!clindqvist From: clindqvist@earthlink.net (Callum Lindqvist) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Dec18.123252.4132@earthlink.net> Date: Sun, 18 Dec 1994 12:32:52 GMT Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: WinVN 0.99.5 Lines: 11 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. Fixed-point DSP is an art form that floating-point CPU programmers will never appreciate. -- Callum Lindqvist *PLONK* filter active for trolls. 486DX2/66 (Linux 1.2.13) - NetBSD 1.0 From dgarcia@u-tokyo.ac.jp Mon Dec 19 19:36:52 1994 Path: ashpoly!bigsur!pacrim!krgate!eunha!u-tokyo!dgarcia From: dgarcia@u-tokyo.ac.jp (Dave García) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Dec19.193652.4380@u-tokyo.ac.jp> Date: Mon, 19 Dec 1994 19:36:52 GMT References: <1994Dec18.123252.4132@earthlink.net> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1994Dec18.123252.4132@earthlink.net>, clindqvist@earthlink.net (Callum Lindqvist) 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. -- Dave García *PLONK* filter active for trolls. Atari Falcon 030 - NetBSD 1.0 From lstewart@delphi.com Tue Dec 20 07:53:52 1994 Path: ashpoly!bigsur!pacrim!jpgate!kamome!delphi!lstewart From: lstewart@delphi.com (Liam Stewart) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Dec20.075352.7932@delphi.com> Date: Tue, 20 Dec 1994 07:53:52 GMT References: <1994Dec18.123252.4132@earthlink.net> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1994Dec18.123252.4132@earthlink.net>, clindqvist@earthlink.net (Callum Lindqvist) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Liam Stewart *PLONK* filter active for trolls. PC-9821Ap2 (NEC) - NetBSD 1.0 From mokonkwo@delphi.com Wed Dec 21 10:19:52 1994 Path: ashpoly!cascade!mxgate!coyoacan!delphi!mokonkwo From: mokonkwo@delphi.com (Matthias Okonkwo) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Dec21.101952.9418@delphi.com> Date: Wed, 21 Dec 1994 10:19:52 GMT References: <1994Dec18.123252.4132@earthlink.net> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: TIN [version 1.2 PL2] Lines: 12 In article <1994Dec18.123252.4132@earthlink.net>, clindqvist@earthlink.net (Callum 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. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. If you are posting from AOL, please read RFC 1036 before posting again. -- Matthias Okonkwo "Row 14. No joke." 486DX4/100 (FreeBSD 2.0.5) / FreeBSD 2.1 From spetrov@mit.edu Fri Dec 23 00:56:52 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!mit!spetrov From: spetrov@mit.edu (Seo-yeon Petrov) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Dec23.005652.2588@mit.edu> Date: Fri, 23 Dec 1994 00:56:52 GMT References: <1994Dec18.123252.4132@earthlink.net> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1994Dec18.123252.4132@earthlink.net>, clindqvist@earthlink.net (Callum 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! Netscape 1.1 crashes when loading large preformatted text. Stick to rn or tin! -- Seo-yeon Petrov | spetrov@mit.edu PGP Key fingerprint: E442 FBF0 D3C6 E4C1 "Keep the channels open."