From lgarcia@panix.com Tue Sep 24 14:24:48 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!panix!lgarcia From: lgarcia@panix.com (Lisa García) Newsgroups: comp.dsp Subject: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Sep24.142448.2587@panix.com> Date: Tue, 24 Sep 1996 14:24:48 GMT Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com 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. Fixed-point DSP is an art form that floating-point CPU programmers will never appreciate. -- Lisa García "We don't sign stars. We build them." Commodore Amiga 500 (1MB OCS) / NEXTSTEP 3.3 From fmartinez@clari.net Wed Sep 25 21:54:48 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!clari!fmartinez From: fmartinez@clari.net (Freya Martínez) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Sep25.215448.2495@clari.net> Date: Wed, 25 Sep 1996 21:54:48 GMT References: <1996Sep24.142448.2587@panix.com> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1996Sep24.142448.2587@panix.com>, lgarcia@panix.com (Lisa García) 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. -- Freya Martínez | fmartinez@clari.net PGP Key fingerprint: 6BBA DF2E 27D6 93F8 "Keep the channels open."