From dsanchez@purdue.edu Wed Nov 22 19:40:09 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!purdue!dsanchez From: dsanchez@purdue.edu (Dave Sánchez) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Nov22.194009.5977@purdue.edu> Date: Wed, 22 Nov 1995 19:40:09 GMT Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 11 Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. 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. -- Dave Sánchez *PLONK* filter active for trolls. Acorn RiscPC 600 - NetBSD 1.0 From givanov@unam.mx Fri Nov 24 09:49:09 1995 Path: ashpoly!cascade!brgate!saturno!unam!givanov From: givanov@unam.mx (Göran Ivanov) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Nov24.094909.2189@unam.mx> Date: Fri, 24 Nov 1995 09:49:09 GMT References: <1995Nov22.194009.5977@purdue.edu> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Nov22.194009.5977@purdue.edu>, dsanchez@purdue.edu (Dave Sánchez) 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. -- Göran Ivanov Practical Peripherals 14.4 @ 33,600 bps "Hold for relay." From jmacdonald@kth.se Fri Nov 24 19:45:09 1995 Path: ashpoly!cascade!brgate!saturno!kth!jmacdonald From: jmacdonald@kth.se (Ji-woo MacDonald) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Nov24.194509.6951@kth.se> Date: Fri, 24 Nov 1995 19:45:09 GMT References: <1995Nov22.194009.5977@purdue.edu> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: NewsWatcher 2.0b24 Lines: 12 In article <1995Nov22.194009.5977@purdue.edu>, dsanchez@purdue.edu (Dave Sánchez) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. > By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- === Ji-woo MacDonald === Dept of Electrical Engineering, Royal Institute of Technology, Stockholm "Marcus is not one man."