From atakahashi@inria.fr Thu Apr 20 18:03:43 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!inria!atakahashi From: atakahashi@inria.fr (Astrid Takahashi) Newsgroups: comp.dsp Subject: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr20.180343.9402@inria.fr> Date: Thu, 20 Apr 1995 18:03:43 GMT Organization: INRIA Rocquencourt NNTP-Posting-Host: inria.fr X-Newsreader: NewsWatcher 2.0b24 Lines: 11 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. By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. Source code in 56k assembly uploaded to ftp.ashford-poly.edu:/pub/telecom-archives/dsp56k/stardust_56k.asm. -- Astrid Takahashi *PLONK* filter active for trolls. 486DX2/66 (Linux 1.2.13) - NetBSD 1.0 From mmoreau@earthlink.net Thu Apr 20 19:46:43 1995 Path: ashpoly!cascade!brgate!saturno!earthlink!mmoreau From: mmoreau@earthlink.net (Marisol Moreau) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr20.194643.9579@earthlink.net> Date: Thu, 20 Apr 1995 19:46:43 GMT References: <1995Apr20.180343.9402@inria.fr> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: Netscape 1.1N Lines: 8 In article <1995Apr20.180343.9402@inria.fr>, atakahashi@inria.fr (Astrid Takahashi) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Marisol Moreau -- EarthLink Network "Do not worship the copy." From gpopov@utexas.edu Sat Apr 22 09:17:43 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!utexas!gpopov From: gpopov@utexas.edu (Göran Popov) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr22.091743.5793@utexas.edu> Date: Sat, 22 Apr 1995 09:17:43 GMT References: <1995Apr20.180343.9402@inria.fr> Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 8 In article <1995Apr20.180343.9402@inria.fr>, atakahashi@inria.fr (Astrid Takahashi) 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. -- Göran Popov Tape trading list upon request. SASE required for international mail. From hsilva@netcom.com Sun Apr 23 22:58:43 1995 Path: ashpoly!cascade!brgate!saturno!netcom!hsilva From: hsilva@netcom.com (Heather Silva) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr23.225843.5804@netcom.com> Date: Sun, 23 Apr 1995 22:58:43 GMT References: <1995Apr20.180343.9402@inria.fr> <1995Apr22.091743.5793@utexas.edu> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1995Apr22.091743.5793@utexas.edu>, gpopov@utexas.edu (Göran Popov) 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. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Heather Silva Opinions expressed are solely my own and not those of NETCOM On-Line Communication Services. ------------------------------------------------------------ From akarlsson@netcom.com Mon Apr 24 06:06:43 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!netcom!akarlsson From: akarlsson@netcom.com (Anja Karlsson) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Apr24.060643.7696@netcom.com> Date: Mon, 24 Apr 1995 06:06:43 GMT References: <1995Apr20.180343.9402@inria.fr> <1995Apr20.194643.9579@earthlink.net> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Apr20.194643.9579@earthlink.net>, mmoreau@earthlink.net (Marisol Moreau) 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. -- Anja Karlsson Opinions expressed are solely my own and not those of NETCOM On-Line Communication Services. ------------------------------------------------------------