From lpopov@utexas.edu Sun Feb 12 21:39:54 1995 Path: ashpoly!cascade!transat!ukc!fennimore!utexas!lpopov From: lpopov@utexas.edu (Lisa Popov) Newsgroups: comp.dsp Subject: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Feb12.213954.5439@utexas.edu> Date: Sun, 12 Feb 1995 21:39:54 GMT Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: WinVN 0.99.5 Lines: 10 Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. Source code in 56k assembly uploaded to ftp.ashford-poly.edu:/pub/telecom-archives/dsp56k/stardust_56k.asm. -- Lisa Popov Tape trading list upon request. SASE required for international mail. From mivanov@netcom.com Sun Feb 12 23:26:54 1995 Path: ashpoly!cascade!mxgate!coyoacan!netcom!mivanov From: mivanov@netcom.com (Mateo Ivanov) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Feb12.232654.9881@netcom.com> Date: Sun, 12 Feb 1995 23:26:54 GMT References: <1995Feb12.213954.5439@utexas.edu> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Feb12.213954.5439@utexas.edu>, lpopov@utexas.edu (Lisa Popov) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Mateo Ivanov | mivanov@netcom.com PGP Key fingerprint: 469D D3D4 F3EA 9623 "Keep the channels open." From htakahashi@u-tokyo.ac.jp Tue Feb 14 16:46:54 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!u-tokyo!htakahashi From: htakahashi@u-tokyo.ac.jp (Heather Takahashi) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Feb14.164654.7118@u-tokyo.ac.jp> Date: Tue, 14 Feb 1995 16:46:54 GMT References: <1995Feb12.213954.5439@utexas.edu> <1995Feb12.232654.9881@netcom.com> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1995Feb12.232654.9881@netcom.com>, mivanov@netcom.com (Mateo Ivanov) 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. -- Heather Takahashi Tape trading list upon request. SASE required for international mail. From mhernandez@delphi.com Wed Feb 15 06:00:54 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!delphi!mhernandez From: mhernandez@delphi.com (Matthias Hernández) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Feb15.060054.4316@delphi.com> Date: Wed, 15 Feb 1995 06:00:54 GMT References: <1995Feb12.213954.5439@utexas.edu> <1995Feb12.232654.9881@netcom.com> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Feb12.232654.9881@netcom.com>, mivanov@netcom.com (Mateo Ivanov) 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. -- Matthias Hernández | mhernandez@delphi.com PGP Key fingerprint: 8A87 67FF 3EF8 7973 "Keep the channels open." From mlaurent@clari.net Thu Feb 16 13:04:54 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!clari!mlaurent From: mlaurent@clari.net (Min-jun Laurent) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Feb16.130454.1047@clari.net> Date: Thu, 16 Feb 1995 13:04:54 GMT References: <1995Feb12.213954.5439@utexas.edu> <1995Feb12.232654.9881@netcom.com> <1995Feb14.164654.7118@u-tokyo.ac.jp> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: TIN [version 1.2 PL2] Lines: 8 In article <1995Feb14.164654.7118@u-tokyo.ac.jp>, htakahashi@u-tokyo.ac.jp (Heather Takahashi) writes: > Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Min-jun Laurent Tape trading list upon request. SASE required for international mail.