Reply by Danne May 15, 20052005-05-15
Thank you all for your comments.
I will investigate the possibility to go into a fixed point DSP.
Best Regards Danne


"Danne" <NoSpam@FakeEMail.Nowhere> skrev i meddelandet
news:6J6ge.23896$d5.171697@newsb.telia.net...
> Hello > I'm looking for a "smaller" floating point DSP (do not need so much > MIPS/MFLOPS). The DSP should have onchip RAM (data) and FLASH > (program+data tables). A more important factor is the powers
consume,
> it should be very low due to battery power. I have found TMS320VC33 > but what are the alternatives? Any experience with the TMS320VC33 is > welcome. > > BR Danne > > >
Reply by May 13, 20052005-05-13
"bhooshaniyer" <bhooshaniyer@gmail.com> writes:

> Randy-- > > >Bhooshan, > > > >I haven't noticed anyone berating your spelling capabilities here so > > Well, it has happened few times,especially when I was in the middle > serious and passionate issues.
I can understand your frustration with those who practice those tactics - they are "below the belt."
> I can understand if you havent noticed, but > some how I assumed you read almost all the threads here.Do not matter now > though.
Sheesh! I do have to do SOME coding around here...
> >your humorous innuendo was indeed lost on me. > > Yeah...That was the bigger tragedy. > > >Compared to the pig-slop > >that passes as English that we often get on this group, this seems > >pretty minor. > > It was pretty minor for sure.Especially since it was a french > expression(was it french),
It may be French as well, but before French and English it was Latin.
> it was not even an english language spelling > mistake. > > Though am not familiar with the usage- "pig-slop",
It's the mix of discarded, half-eaten food and garbage that you feed the pigs with.
> am assuming that you > are not very fond of the broken english variety...
Ayup.
> But you should cut some > holy slack for the non-native english speakers as well.
I was not the one who attacked. I think I can tell the difference between technical incompetence and a language barrier, and I would not berate the English of anyone who is honestly seeking answers to a DSP question here. But I admit that there may be other English-speaking folks who think the world revolves around them. -- Randy Yates Sony Ericsson Mobile Communications Research Triangle Park, NC, USA randy.yates@sonyericsson.com, 919-472-1124
Reply by bhooshaniyer May 13, 20052005-05-13
Randy--

>Bhooshan, > >I haven't noticed anyone berating your spelling capabilities here so
Well, it has happened few times,especially when I was in the middle serious and passionate issues.I can understand if you havent noticed, but some how I assumed you read almost all the threads here.Do not matter now though.
>your humorous innuendo was indeed lost on me.
Yeah...That was the bigger tragedy.
>Compared to the pig-slop >that passes as English that we often get on this group, this seems >pretty minor.
It was pretty minor for sure.Especially since it was a french expression(was it french), it was not even an english language spelling mistake. Though am not familiar with the usage- "pig-slop", am assuming that you are not very fond of the broken english variety...But you should cut some holy slack for the non-native english speakers as well. --Bhooshan This message was sent using the Comp.DSP web interface on www.DSPRelated.com
Reply by May 13, 20052005-05-13
"bhooshaniyer" <bhooshaniyer@gmail.com> writes:

> Randy-- > > >> Did you mean non sequit*u*r? > > > >I believe my meaning was clear and the intent of your > >post is to fault for a spelling error. > > You apparently missed the humor(self-deprecating,actually...I get picked > on all the time for my bad spelling...that was a lame attempt at pointing > one out from my side...)in my post, so there is no point trying to telling > you that it was a failed attempt at humor.Never the less you must know that > I did not intend offence(why would you think otherwise? Because I argue at > times?) and I did believe your intent and argument was self evident.
Bhooshan, I haven't noticed anyone berating your spelling capabilities here so your humorous innuendo was indeed lost on me. Compared to the pig-slop that passes as English that we often get on this group, this seems pretty minor. -- Randy Yates Sony Ericsson Mobile Communications Research Triangle Park, NC, USA randy.yates@sonyericsson.com, 919-472-1124
Reply by Jon Harris May 13, 20052005-05-13
"Randy Yates" <randy.yates@sonyericsson.com> wrote in message
news:xxp7ji3fcz3.fsf@usrts005.corpusers.net...
> "Jon Harris" <jon_harrisTIGER@hotmail.com> writes: > > [...] > > Jon, > > Stuff it, dude. The original poster stated: > > I'm looking for a "smaller" floating point DSP (do not need so much > MIPS/MFLOPS). > > Thus my suggestion was reasonable.
I must admit, I never read the OP, but jumped in late. The discussion seemed to have turned to the general topic of fixed point emulation of floating point, so that's where I was coming from. But given the OP's requirements, your suggest is reasonable. Consider it "stuffed". :-)
Reply by bhooshaniyer May 13, 20052005-05-13
Randy--

>> Did you mean non sequit*u*r? > >I believe my meaning was clear and the intent of your >post is to fault for a spelling error.
You apparently missed the humor(self-deprecating,actually...I get picked on all the time for my bad spelling...that was a lame attempt at pointing one out from my side...)in my post, so there is no point trying to telling you that it was a failed attempt at humor.Never the less you must know that I did not intend offence(why would you think otherwise? Because I argue at times?) and I did believe your intent and argument was self evident. --Bhooshan This message was sent using the Comp.DSP web interface on www.DSPRelated.com
Reply by May 13, 20052005-05-13
"Jon Harris" <jon_harrisTIGER@hotmail.com> writes:
> [...]
Jon, Stuff it, dude. The original poster stated: I'm looking for a "smaller" floating point DSP (do not need so much MIPS/MFLOPS). Thus my suggestion was reasonable. -- Randy Yates Sony Ericsson Mobile Communications Research Triangle Park, NC, USA randy.yates@sonyericsson.com, 919-472-1124
Reply by May 13, 20052005-05-13
"bhooshaniyer" <bhooshaniyer@gmail.com> writes:

> Randy Yates wrote: > >Your conclusion is a non-sequitor. > > Did you mean non sequit*u*r?
I believe my meaning was clear and the intent of your post is to fault for a spelling error. -- Randy Yates Sony Ericsson Mobile Communications Research Triangle Park, NC, USA randy.yates@sonyericsson.com, 919-472-1124
Reply by Jon Harris May 13, 20052005-05-13
"Randy Yates" <yates@ieee.org> wrote in message news:psvvdcex.fsf@ieee.org...
> Hi Jon, > > Let me respond to your points below. > > "Jon Harris" <jon_harrisTIGER@hotmail.com> writes: > > > "Randy Yates" <randy.yates@sonyericsson.com> wrote in message > > news:xxpmzr0fg7o.fsf@usrts005.corpusers.net... > >> "DigitalSignal" <digitalsignal999@yahoo.com> writes: > >> > >> > I have benchmarked the floating point software library for a fixed > >> > point processor. The inefficiency ratio is about 50 to 100. In the > >> > other words, you need 50 to 100 instruction cycles of a fixed point > >> > processor to implement one floating point instruction. This should not > >> > come as a surprise if you consider all the PUSH and POPs when a > >> > subroutine is called. > >> > > >> > So for the people who frequently need floating point operations, > >> > fixed-point processor is hardly the solution. > >> > >> Let's see - if I need 10,000 floating point operations per second, > >> then, at a factor of 100:1, I need 1 MIPS - well within reach of any > >> fixed-point DSP developed within the last 10 years. > >> > >> Your conclusion is a non-sequitor. The decision depends on the > >> horsepower required. > > > > Another way to say it which may be more to your liking is that the fixed
point
> > DSP emulating a floating-point will need to run 50-100 times faster than a > > similar floating point DSP. This implies significantly higher cost, > > The only way I see that this can be true is if the user's horsepower > requirement dictated a special high-speed version of the fixed-point > DSP, with a correspondingly high cost due to the reduced > yield.
With a 50-100x performance hit, unless the application was pretty light-weight the scenario you describe seems pretty likely. Worse yet would be if the algorithm taxed today's higher-speed floating point DSPs, say a SHARC runing at 300 MHz. The 15-30GHz fixed point processor to emulate that would be pretty pricey (and power hungry)! But assuming the processing requirement could be satisifed by say 1 MFLOP, then a 50-100 MIP fixed point guy would be a fine solution. It really depends on where the application sits relative to todays technology "sweet spots".
> Otherwise I would think just the opposite is true - the > floating point part is going to be costlier due to the extra silicon > required to implement the floating point logic. > > In fact, if the horsepower requirements were commensurate with a > moderately-priced fixed-point DSP, this would be a classic example of > trading off hardware for time of execution, similar to using > bit-serial logic in an FGPA or ASIC. > > > power consumption, > > That depends on the ratio of mA/MIP to mA/MFLOP, I would guess. If the > ratio is less than 1:50 or so, it would be wash (or even an advantage) > power-wise.
Do you think the power hit for floating point is really on the order of 50x (assuming the same word-length)? I think in an ideal world, if you could construct a floating-point DSP to exatly do a particular floating-point job or construct a fixed-point DSP to do the same job at 50-100 performance hit, the floating-point is going to win hands down in both cost and power. (I'm just guessing, but I would think it would take somewhere around 2-5x the silicon to make a floating-point MAC vs. a fixed-point. Ray Andraka might know.) But in practice, there just aren't a lot of cheap, relatively slow floating-point DSPs out there, and you have a lot more choices in the fixed point world. So with real-world parts and light to moderate processing requirements, the fixed point emulation might work out well.
> > etc.. But like you pointed out, if you have a very small > > horsepower need, software emulation may be just fine. Personally, I've
never
> > had the luxury of using a processor that is 50-100 times faster than it
needs to
> > be in a work project! :-) > > I guess I don't see it being such an unfathomable situation, thus the
suggestion
> seemed appropriate to me.
In my experience, the cheapest processor that will do the job is designed in, and if there is overhead, extra features are added to fill up overhead (and then some)! Having 2x the required processing power would be a luxury for me, so 50-100x would definitely be "unfathomable"! But I'm sure others have had significantly different experiences. I suppose if you were using an off-the-shelf platform rather than something custom-designed, you might be more likely to have a large amount of overhead.
Reply by bhooshaniyer May 13, 20052005-05-13
Randy Yates wrote:
>Your conclusion is a non-sequitor.
Did you mean non sequit*u*r? --Bhooshan This message was sent using the Comp.DSP web interface on www.DSPRelated.com