From hvasiliev@uu.net Wed Jun 28 17:30:17 1995 Path: ashpoly!cascade!transat!ukc!fennimore!uu!hvasiliev From: hvasiliev@uu.net (Hana Vasiliev) Newsgroups: comp.dsp Subject: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jun28.173017.4484@uu.net> Date: Wed, 28 Jun 1995 17:30:17 GMT Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: TIN [version 1.2 PL2] Lines: 10 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. Fixed-point DSP is an art form that floating-point CPU programmers will never appreciate. -- Hana Vasiliev Tape trading list upon request. SASE required for international mail. From drobertson@titech.ac.jp Thu Jun 29 05:35:17 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!titech!drobertson From: drobertson@titech.ac.jp (Dave Robertson) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jun29.053517.5830@titech.ac.jp> Date: Thu, 29 Jun 1995 05:35:17 GMT References: <1995Jun28.173017.4484@uu.net> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Jun28.173017.4484@uu.net>, hvasiliev@uu.net (Hana Vasiliev) 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. -- Dave Robertson *PLONK* filter active for trolls. Macintosh IIfx - NetBSD 1.0