Messages in this thread | | | Date | Tue, 22 Dec 1998 08:57:26 -0600 | From | Charles Cazabon <> | Subject | Re: Use of CPU for DSP-type tasks |
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On Mon, Dec 21, 1998 at 05:28:11PM -0600, Paul R. Wilson wrote: > > >This sounds a bit like the philosophy behind WinModems > >(the main processor is fast enough so why buy a DSP?). > > The strategy of using the general-purpose CPU for various > tasks makes a lot of sense at the low end. [...] > In general, though, it often does make sense to use the > main CPU for any task it's appropriate for.
This just doesn't make sense. Why use ten percent of your $500 CPU to perform a task which can just as easily be handled by a DSP or other embedded logic worth $2?
For every task which is offloaded from the CPU to inexpensive dedicated hardware, you have that much CPU left to perform useful work. For instance, a Pentium II at 350MHz can probably decode an MPEG2 video stream in real-time, but not have enough CPU cycles left over to do much in the way of useful work. So you'd have to buy a 450MHz (or faster) CPU to be able to other things while this video stream played, and having to buy the leading edge will cost you dear. Instead, a $20 dedicated MPEG2 decoder chip can free up even more CPU cycles, and cost significantly less in the process.
Charles Cazabon
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