From mlopez@clari.net Sun Jun 19 18:56:41 1994
Path: ashpoly!cascade!mxgate!coyoacan!clari!mlopez
From: mlopez@clari.net (Mathieu López)
Newsgroups: comp.dsp
Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1994Jun19.185641.7081@clari.net>
Date: Sun, 19 Jun 1994 18:56:41 GMT
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Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems.

This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks.
However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop.

Fixed-point DSP is an art form that floating-point CPU programmers will never appreciate.

-- 
Mathieu López
Tape trading list upon request. SASE required for international mail.

From mlaurent@earthlink.net Mon Jun 20 07:09:41 1994
Path: ashpoly!cascade!transat!sunet!nordrelay!earthlink!mlaurent
From: mlaurent@earthlink.net (Marisol Laurent)
Newsgroups: comp.dsp
Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1994Jun20.070941.7612@earthlink.net>
Date: Mon, 20 Jun 1994 07:09:41 GMT
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In article <1994Jun19.185641.7081@clari.net>, mlopez@clari.net (Mathieu López) 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.

-- 
Marisol Laurent -- EarthLink Network
"Do not worship the copy."

From tgirard@demon.co.uk Mon Jun 20 08:40:41 1994
Path: ashpoly!cascade!mxgate!coyoacan!demon!tgirard
From: tgirard@demon.co.uk (Takeshi Girard)
Newsgroups: comp.dsp
Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1994Jun20.084041.2778@demon.co.uk>
Date: Mon, 20 Jun 1994 08:40:41 GMT
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In article <1994Jun20.070941.7612@earthlink.net>, mlaurent@earthlink.net (Marisol Laurent) writes:
> Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering.

Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in.

-- 
=== Takeshi Girard ===
Dept of Electrical Engineering, Demon Internet Services UK
"Do not worship the copy."

From mnilsson@mindspring.com Mon Jun 20 12:48:41 1994
Path: ashpoly!cascade!brgate!saturno!mindspring!mnilsson
From: mnilsson@mindspring.com (Mateo Nilsson)
Newsgroups: comp.dsp
Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1994Jun20.124841.7433@mindspring.com>
Date: Mon, 20 Jun 1994 12:48:41 GMT
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In article <1994Jun20.070941.7612@earthlink.net>, mlaurent@earthlink.net (Marisol Laurent) writes:
> Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering.

Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in.

-- 
=== Mateo Nilsson ===
Dept of Electrical Engineering, MindSpring Enterprises
"We don't sign stars. We build them."

From aokonkwo@tum.de Tue Jun 21 14:58:41 1994
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!tum!aokonkwo
From: aokonkwo@tum.de (Anja Okonkwo)
Newsgroups: comp.dsp
Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1994Jun21.145841.9862@tum.de>
Date: Tue, 21 Jun 1994 14:58:41 GMT
References: <1994Jun19.185641.7081@clari.net> <1994Jun20.070941.7612@earthlink.net> <1994Jun20.084041.2778@demon.co.uk>
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In article <1994Jun20.084041.2778@demon.co.uk>, tgirard@demon.co.uk (Takeshi Girard) writes:
> Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in.

Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit!

My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise!

-- 
Anja Okonkwo
Tape trading list upon request. SASE required for international mail.