From vsantos@illinois.edu Sat Jul 22 23:05:18 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!illinois!vsantos From: vsantos@illinois.edu (Valeria Santos) Newsgroups: comp.dsp Subject: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jul22.230518.2047@illinois.edu> Date: Sat, 22 Jul 1995 23:05:18 GMT Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: WinVN 0.99.5 Lines: 10 Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. 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. -- Valeria Santos Tape trading list upon request. SASE required for international mail. From rkarlsson@cam.ac.uk Mon Jul 24 00:27:18 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!cam!rkarlsson From: rkarlsson@cam.ac.uk (Rodrigo Karlsson) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jul24.002718.4352@cam.ac.uk> Date: Mon, 24 Jul 1995 00:27:18 GMT References: <1995Jul22.230518.2047@illinois.edu> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Jul22.230518.2047@illinois.edu>, vsantos@illinois.edu (Valeria Santos) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- === Rodrigo Karlsson === Dept of Electrical Engineering, University of Cambridge Computer Laboratory "The hatch is open. Is anyone listening?" From erobertson@tum.de Mon Jul 24 03:04:18 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!tum!erobertson From: erobertson@tum.de (Elaine Robertson) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jul24.030418.4528@tum.de> Date: Mon, 24 Jul 1995 03:04:18 GMT References: <1995Jul22.230518.2047@illinois.edu> <1995Jul24.002718.4352@cam.ac.uk> Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1995Jul24.002718.4352@cam.ac.uk>, rkarlsson@cam.ac.uk (Rodrigo Karlsson) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit! -- Elaine Robertson Tape trading list upon request. SASE required for international mail. From ikim@illinois.edu Tue Jul 25 22:06:18 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!illinois!ikim From: ikim@illinois.edu (Ines Kim) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jul25.220618.7506@illinois.edu> Date: Tue, 25 Jul 1995 22:06:18 GMT References: <1995Jul22.230518.2047@illinois.edu> <1995Jul24.002718.4352@cam.ac.uk> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Jul24.002718.4352@cam.ac.uk>, rkarlsson@cam.ac.uk (Rodrigo Karlsson) 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. -- Ines Kim "Tape doesn't lie at 02:14. Ears do." Amiga 3000T / TOS 4.04 From hivanov@unam.mx Thu Jul 27 02:46:18 1995 Path: ashpoly!cascade!brgate!saturno!unam!hivanov From: hivanov@unam.mx (Hugo Ivanov) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jul27.024618.8864@unam.mx> Date: Thu, 27 Jul 1995 02:46:18 GMT References: <1995Jul22.230518.2047@illinois.edu> <1995Jul24.002718.4352@cam.ac.uk> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1995Jul24.002718.4352@cam.ac.uk>, rkarlsson@cam.ac.uk (Rodrigo Karlsson) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Hugo Ivanov Zyxel U-1496E @ 14,400 bps "When every node is whole, the channel opens."