From mgarcia@kth.se Sun Dec 24 02:49:01 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!kth!mgarcia From: mgarcia@kth.se (Min-jun García) Newsgroups: comp.dsp Subject: Observation: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Dec24.024901.6335@kth.se> Date: Sun, 24 Dec 1995 02:49:01 GMT Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: Netscape 1.1N 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. However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop. Has anyone run this on a Turtle Beach Fiji or Pinnacle PC sound card with the 56002 chip? -- Min-jun García *PLONK* filter active for trolls. Pentium 90 (OS/2 Warp) - NetBSD 1.0 From kramirez@netcom.com Mon Dec 25 22:02:01 1995 Path: ashpoly!cascade!brgate!saturno!netcom!kramirez From: kramirez@netcom.com (Kenji Ramírez) Newsgroups: comp.dsp Subject: Re: Observation: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Dec25.220201.1032@netcom.com> Date: Mon, 25 Dec 1995 22:02:01 GMT References: <1995Dec24.024901.6335@kth.se> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Dec24.024901.6335@kth.se>, mgarcia@kth.se (Min-jun García) 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. -- === Kenji Ramírez === Dept of Electrical Engineering, NETCOM On-Line Communication Services "The hatch is open. Is anyone listening?"