From nsokolov@uu.net Fri Aug 12 22:01:46 1994 Path: ashpoly!cascade!bigsur!uu!nsokolov From: nsokolov@uu.net (Nadia Sokolov) Newsgroups: comp.dsp Subject: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Aug12.220146.3136@uu.net> Date: Fri, 12 Aug 1994 22:01:46 GMT Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: TIN [version 1.2 PL2] 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. This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. Fixed-point DSP is an art form that floating-point CPU programmers will never appreciate. -- Nadia Sokolov Tape trading list upon request. SASE required for international mail. From mkim@purdue.edu Sun Aug 14 08:45:46 1994 Path: ashpoly!cascade!brgate!saturno!purdue!mkim From: mkim@purdue.edu (Mathieu Kim) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Aug14.084546.3691@purdue.edu> Date: Sun, 14 Aug 1994 08:45:46 GMT References: <1994Aug12.220146.3136@uu.net> Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 8 In article <1994Aug12.220146.3136@uu.net>, nsokolov@uu.net (Nadia Sokolov) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Mathieu Kim Tape trading list upon request. SASE required for international mail. From lschneider@utexas.edu Mon Aug 15 11:21:46 1994 Path: ashpoly!cascade!transat!ukc!fennimore!utexas!lschneider From: lschneider@utexas.edu (Liam Schneider) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Aug15.112146.7332@utexas.edu> Date: Mon, 15 Aug 1994 11:21:46 GMT References: <1994Aug12.220146.3136@uu.net> <1994Aug14.084546.3691@purdue.edu> Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1994Aug14.084546.3691@purdue.edu>, mkim@purdue.edu (Mathieu Kim) writes: > Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. Netscape 1.1 crashes when loading large preformatted text. Stick to rn or tin! -- Liam Schneider Tape trading list upon request. SASE required for international mail. From ksantos@clari.net Tue Aug 16 06:19:46 1994 Path: ashpoly!cascade!transat!ukc!fennimore!clari!ksantos From: ksantos@clari.net (Katrin Santos) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Aug16.061946.4467@clari.net> Date: Tue, 16 Aug 1994 06:19:46 GMT References: <1994Aug12.220146.3136@uu.net> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1994Aug12.220146.3136@uu.net>, nsokolov@uu.net (Nadia Sokolov) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Katrin Santos "A soul is not exclusive to biology." Pentium 90 (OS/2 Warp) / FreeBSD 2.1 From twatanabe@mit.edu Thu Aug 18 04:02:46 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!mit!twatanabe From: twatanabe@mit.edu (Tyler Watanabe) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Aug18.040246.1115@mit.edu> Date: Thu, 18 Aug 1994 04:02:46 GMT References: <1994Aug12.220146.3136@uu.net> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1994Aug12.220146.3136@uu.net>, nsokolov@uu.net (Nadia Sokolov) 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. -- Tyler Watanabe -- Massachusetts Institute of Technology "In theory there is no difference between theory and practice."