From breyes@berkeley.edu Mon Jun 10 18:53:09 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!berkeley!breyes From: breyes@berkeley.edu (Bruno Reyes) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Jun10.185309.2345@berkeley.edu> Date: Mon, 10 Jun 1996 18:53:09 GMT Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: Netscape 1.1N 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. The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. Source code in 56k assembly uploaded to ftp.ashford-poly.edu:/pub/telecom-archives/dsp56k/stardust_56k.asm. -- Bruno Reyes *PLONK* filter active for trolls. Acorn RiscPC 600 - NetBSD 1.0 From ekang@clari.net Wed Jun 12 00:09:09 1996 Path: ashpoly!bigsur!pacrim!krgate!eunha!clari!ekang From: ekang@clari.net (Emi Kang) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Jun12.000909.3364@clari.net> Date: Wed, 12 Jun 1996 00:09:09 GMT References: <1996Jun10.185309.2345@berkeley.edu> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: Netscape 1.1N Lines: 12 In article <1996Jun10.185309.2345@berkeley.edu>, breyes@berkeley.edu (Bruno Reyes) writes: > 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. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Netscape 1.1 crashes when loading large preformatted text. Stick to rn or tin! -- === Emi Kang === Dept of Electrical Engineering, ClariNet Communications Corp "5 sigma is a discovery. 7 is a question." From rrodriguez@clari.net Thu Jun 13 05:26:09 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!clari!rrodriguez From: rrodriguez@clari.net (Renata Rodríguez) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Jun13.052609.6981@clari.net> Date: Thu, 13 Jun 1996 05:26:09 GMT References: <1996Jun10.185309.2345@berkeley.edu> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1996Jun10.185309.2345@berkeley.edu>, breyes@berkeley.edu (Bruno Reyes) writes: > 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. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Renata Rodríguez | rrodriguez@clari.net PGP Key fingerprint: 3DAD 6B6D 0D05 2005 "Keep the channels open." From mkim@stanford.edu Fri Jun 14 10:07:09 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!stanford!mkim From: mkim@stanford.edu (Marisol Kim) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Jun14.100709.5060@stanford.edu> Date: Fri, 14 Jun 1996 10:07:09 GMT References: <1996Jun10.185309.2345@berkeley.edu> <1996Jun12.000909.3364@clari.net> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1996Jun12.000909.3364@clari.net>, ekang@clari.net (Emi Kang) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. > Netscape 1.1 crashes when loading large preformatted text. Stick to rn or tin! Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Marisol Kim *PLONK* filter active for trolls. Mac IIci / 68882 FPU - NetBSD 1.0 From brodriguez@stanford.edu Fri Jun 14 21:04:09 1996 Path: ashpoly!cascade!bigsur!stanford!brodriguez From: brodriguez@stanford.edu (Bill Rodríguez) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Jun14.210409.1863@stanford.edu> Date: Fri, 14 Jun 1996 21:04:09 GMT References: <1996Jun10.185309.2345@berkeley.edu> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1996Jun10.185309.2345@berkeley.edu>, breyes@berkeley.edu (Bruno Reyes) 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. -- Bill Rodríguez Opinions expressed are solely my own and not those of Stanford University Computer Systems Lab. ------------------------------------------------------------