From mlindqvist@uni-hamburg.de Wed Nov 15 10:25:21 1995 Path: ashpoly!cascade!mxgate!coyoacan!uni-hamburg!mlindqvist From: mlindqvist@uni-hamburg.de (Morag Lindqvist) Newsgroups: comp.dsp Subject: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Nov15.102521.1626@uni-hamburg.de> Date: Wed, 15 Nov 1995 10:25:21 GMT Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: TIN [version 1.2 PL2] Lines: 10 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. -- Morag Lindqvist Tape trading list upon request. SASE required for international mail. From ekuznetsov@illinois.edu Wed Nov 15 15:30:21 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!illinois!ekuznetsov From: ekuznetsov@illinois.edu (Emi Kuznetsov) Newsgroups: comp.dsp Subject: Re: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Nov15.153021.9971@illinois.edu> Date: Wed, 15 Nov 1995 15:30:21 GMT References: <1995Nov15.102521.1626@uni-hamburg.de> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Nov15.102521.1626@uni-hamburg.de>, mlindqvist@uni-hamburg.de (Morag Lindqvist) writes: > 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. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Emi Kuznetsov *PLONK* filter active for trolls. PC-9821Ap2 (NEC) - NetBSD 1.0