From mnakamura@kth.se Sat Jul 27 17:36:56 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!kth!mnakamura From: mnakamura@kth.se (Matthias Nakamura) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Jul27.173656.5814@kth.se> Date: Sat, 27 Jul 1996 17:36:56 GMT Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: Netscape 1.1N 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. Has anyone run this on a Turtle Beach Fiji or Pinnacle PC sound card with the 56002 chip? -- Matthias Nakamura "Do not worship the copy." Macintosh IIfx / Linux 1.2.13 From tsokolov@mindspring.com Sun Jul 28 18:12:56 1996 Path: ashpoly!cascade!bigsur!mindspring!tsokolov From: tsokolov@mindspring.com (Tomas Sokolov) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Jul28.181256.9096@mindspring.com> Date: Sun, 28 Jul 1996 18:12:56 GMT References: <1996Jul27.173656.5814@kth.se> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996Jul27.173656.5814@kth.se>, mnakamura@kth.se (Matthias Nakamura) 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. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Tomas Sokolov -- MindSpring Enterprises "5 sigma is a discovery. 7 is a question." From jlaurent@titech.ac.jp Tue Jul 30 13:29:56 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!titech!jlaurent From: jlaurent@titech.ac.jp (Joachim Laurent) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Jul30.132956.1265@titech.ac.jp> Date: Tue, 30 Jul 1996 13:29:56 GMT References: <1996Jul27.173656.5814@kth.se> <1996Jul28.181256.9096@mindspring.com> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1996Jul28.181256.9096@mindspring.com>, tsokolov@mindspring.com (Tomas Sokolov) writes: > Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. PGP Public key available via finger or upon request. -- Joachim Laurent "They will send a copy in my place." Sun 3/60 (SunOS 4.1.1) / System 7.5.1