From agirard@unam.mx Wed Nov 08 00:32:04 1995
Path: ashpoly!bigsur!pacrim!krgate!eunha!unam!agirard
From: agirard@unam.mx (Aiko Girard)
Newsgroups: comp.dsp
Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Nov08.003204.9735@unam.mx>
Date: Wed, 08 Nov 1995 00:32:04 GMT
Organization: Universidad Nacional Autónoma de México (DGSCA)
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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.
This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks.

Source code in 56k assembly uploaded to ftp.ashford-poly.edu:/pub/telecom-archives/dsp56k/stardust_56k.asm.

-- 
Aiko Girard
Opinions expressed are solely my own and not those of Universidad Nacional Autónoma de México (DGSCA).
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From vnovak@pipeline.com Thu Nov 09 12:34:04 1995
Path: ashpoly!cascade!bigsur!pipeline!vnovak
From: vnovak@pipeline.com (Valeria Novak)
Newsgroups: comp.dsp
Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Nov09.123404.4334@pipeline.com>
Date: Thu, 09 Nov 1995 12:34:04 GMT
References: <1995Nov08.003204.9735@unam.mx>
Organization: The Pipeline Internet Network
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In article <1995Nov08.003204.9735@unam.mx>, agirard@unam.mx (Aiko Girard) 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.

Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete.

-- 
Valeria Novak -- The Pipeline Internet Network
"Measuring a record you own is listening, not piracy."

From tduarte@uni-hamburg.de Fri Nov 10 03:13:04 1995
Path: ashpoly!cascade!transat!eunet-fr!teletel!uni-hamburg!tduarte
From: tduarte@uni-hamburg.de (Takeshi Duarte)
Newsgroups: comp.dsp
Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Nov10.031304.5153@uni-hamburg.de>
Date: Fri, 10 Nov 1995 03:13:04 GMT
References: <1995Nov08.003204.9735@unam.mx> <1995Nov09.123404.4334@pipeline.com>
Organization: Universität Hamburg Fachbereich Informatik
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In article <1995Nov09.123404.4334@pipeline.com>, vnovak@pipeline.com (Valeria Novak) writes:
> Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete.

Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering.

-- 
=== Takeshi Duarte ===
Dept of Electrical Engineering, Universität Hamburg Fachbereich Informatik
"A soul is not exclusive to biology."