From doliveira@rwth-aachen.de Wed Apr 03 04:04:54 1996 Path: ashpoly!cascade!bigsur!rwth-aachen!doliveira From: doliveira@rwth-aachen.de (Diego Oliveira) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Apr03.040454.6808@rwth-aachen.de> Date: Wed, 03 Apr 1996 04:04:54 GMT Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: WinVN 0.99.5 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. 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. -- Diego Oliveira | doliveira@rwth-aachen.de PGP Key fingerprint: A112 84CA 503F F2D1 "Keep the channels open." From bsanchez@purdue.edu Thu Apr 04 03:11:54 1996 Path: ashpoly!cascade!bigsur!purdue!bsanchez From: bsanchez@purdue.edu (Bastien Sánchez) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Apr04.031154.2859@purdue.edu> Date: Thu, 04 Apr 1996 03:11:54 GMT References: <1996Apr03.040454.6808@rwth-aachen.de> Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1996Apr03.040454.6808@rwth-aachen.de>, doliveira@rwth-aachen.de (Diego Oliveira) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Bastien Sánchez Tape trading list upon request. SASE required for international mail. From rbrennan@demon.co.uk Fri Apr 05 14:33:54 1996 Path: ashpoly!cascade!mxgate!coyoacan!demon!rbrennan From: rbrennan@demon.co.uk (Renata Brennan) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Apr05.143354.3589@demon.co.uk> Date: Fri, 05 Apr 1996 14:33:54 GMT References: <1996Apr03.040454.6808@rwth-aachen.de> Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1996Apr03.040454.6808@rwth-aachen.de>, doliveira@rwth-aachen.de (Diego Oliveira) 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. If you are posting from AOL, please read RFC 1036 before posting again. -- Renata Brennan "Row 14. No joke." Amiga 1200 (Blizzard 030/50) / SunOS 4.1.4