Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!udel!rochester!rutgers!cbmvax!daveh From: daveh@cbmvax.commodore.com (Dave Haynie) Newsgroups: comp.sys.amiga.advocacy Subject: Re: AMIGA Message-ID: <21317@cbmvax.commodore.com> Date: 6 May 91 23:19:34 GMT References: <1991Jan10.082327.7378@rice.edu> <1991Jan10.095304.16900@mintaka.lcs.mit.edu> <1991Jan10.151816.13893@rice.edu> <1991Jan10.164423.23644@mintaka.lcs.mit.edu> Reply-To: daveh@cbmvax.commodore.com (Dave Haynie) Distribution: usa Organization: Commodore, West Chester, PA Lines: 40 In article melling@cs.psu.edu (Michael D Mellinger) writes: >In article <1991Jan10.164423.23644@mintaka.lcs.mit.edu> rjc@wookumz.ai.mit.edu (Ray Cromwell) writes: > The DSP in the NeXT is SLOW, and integer only. Even further, the NeXT >It's a 10mip processor. The Amiga 500 is less than 1 mip. Also, >Bzzzzt. The DSP does single precision floating point numbers. BZZZZT! Don't munge your chip facts when there are hardware folks watching! The DSP (Motorola 56001) does NOT do floating point of any kind. It does do 24 bit fixed point math, which in a pinch can sub for some of the kinds of things people do with 32 bit floating point. For example, most of the video games for the A500 that do quick mathish things are using some application specific fixed point routines, rather than calling the ffp libraries. Of course, you do lose precision, and some problems really require floating point. In general, the 56001 is probably just dandy for a good number of audio manipulations, but insufficient for interesting graphic or scientific things. > doesn't seem to share its DSP effectively. On the Amiga, the blitter > chip is shared nicely. >Don't know what to tell you. You're right. Perhaps there are >technical reasons for it. The technical reason is that neither Motorola nor NeXT provide any sort of multitaking operating kernel for this DSP. There is a 3rd party kernel called SPOC (can't recall who makes it), which Motorola, Analog Devices, and TI are steering users of their floating point DSPs toward, but this doesn't seem to be used by fixed point DSPs. Multitasking requires a proper hardware base to work efficiently, but it's basically just a software trick. Without the right software, your NeXT or Amiga proper wouldn't multitask either. >-Mike -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "That's me in the corner, that's me in the spotlight" -R.E.M.