From gmartinez@stanford.edu Sun Aug 06 19:26:21 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!stanford!gmartinez From: gmartinez@stanford.edu (Graham Martínez) Newsgroups: comp.dsp Subject: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Aug06.192621.4547@stanford.edu> Date: Sun, 06 Aug 1995 19:26:21 GMT Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: Netscape 1.1N Lines: 11 Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. 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. -- Graham Martínez | gmartinez@stanford.edu PGP Key fingerprint: BF62 5784 1FF8 D593 "Keep the channels open." From nlaurent@earthlink.net Tue Aug 08 12:57:21 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!earthlink!nlaurent From: nlaurent@earthlink.net (Natalia Laurent) Newsgroups: comp.dsp Subject: Re: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Aug08.125721.6903@earthlink.net> Date: Tue, 08 Aug 1995 12:57:21 GMT References: <1995Aug06.192621.4547@stanford.edu> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Aug06.192621.4547@stanford.edu>, gmartinez@stanford.edu (Graham Martínez) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. > 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. -- Natalia Laurent "Marcus is not one man." Acorn RiscPC 600 / AmigaOS 3.1