[Speex-dev] Another ? about Speex and CPU

dbazinet at sunex.ca dbazinet at sunex.ca
Wed Feb 29 20:29:35 PST 2012


Yes, it does and thanks for the fast answer!

The AVR32 runs at same speed but has a built in floating point unit  
for float calcs and a DSP instruction Set. But If I use the fixed  
point version I guess it doesn't change anything then.

So another question:
- Is there a difference of performance/quality between the floating  
point and the fixed point? Actually, what's the main difference?

Thanks again.
Dominic

Quoting Jean-Marc Valin <jmvalin at jmvalin.ca>:

> I don't know the AVR32 chip. However for an ARM7TDMI running at 50 MHz,
> assuming a good compiler and some hand-coded assembly, you would be very
> close to the achievable limit (couldn't say on which side). So if your
> AVR32 is faster than an ARM7TDMI, it's likely achievable. If it's
> slower, then it's likely not achievable.
>
> Hope that helps,
>
> 	Jean-Marc
>
> On 12-02-29 10:21 PM, dbazinet at sunex.ca wrote:
>> Hello,
>>
>> I am interested to use Speex but need to know If I can use it under
>> our project's constraint. We need to use a low cost micro controller
>> on a very small PCB. This means there's no space for an external DSP
>> unit.
>>
>> Can someone tell me if using an AVR32 (Atmel uc) which has a floating
>> point calculation unit and DSP instruction set and running at ~50Mhz
>> for a narrow band 8Kbps sampling rate maybe be feasible or out of reach?
>>
>> AT32UC3C0512C:
>> Low Power 32-bit AVR® Microcontroller
>> - Compact Single-cycle RISC Instruction Set Including DSP Instruction Set
>> - Built-in Floating-Point Processing Unit (FPU)
>> - Read-Modify-Write Instructions and Atomic Bit Manipulation
>> - Performing 1.49 DMIPS / MHz
>> o Up to 91 DMIPS Running at 66 MHz from Flash (1 Wait-State)
>> o Up to 49 DMIPS Running at 33 MHz from Flash (0 Wait-State)
>>
>> Or
>>
>> An ARM7TDMI core running at ~50Mhz for a narrow band 8Kbps sampling rate?
>>
>> I need to know this before I get deeper into Speex.
>>
>> Thanks a lot!
>> Dominic Bazinet
>>
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>> Speex-dev at xiph.org
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>>
>>
>
>




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