Eugene
Guest
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 Posted:
Wed Dec 22, 2004 1:07 pm Post subject:
FFT build with DSP |
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Hello,
the DATA typ ist "shot int" type.
you wrote:
"At first glance I would make sure that the variables prueftest[],
prueftest2[ ] are aligned on 2*nx = 2*256 = 512"
why is nx=256, nx=NX=128, also variables prueftest(), and prueftest2()
have a size of SINE_TABLE_SIZE=256=2*NX=2*128
or do you mind something else?
in the example rfft will be not use #pragma DATA_SECTION,
but I will read about it.
I will see the example rfft one more time.
thanks
I wish you a merry Christmas |
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Shawn Steenhagen
Guest
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| Posted:
Thu Dec 23, 2004 10:47 pm Post subject:
Re: FFT build with DSP |
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"Eugene" <johnbesel@web.de> wrote in message
news:6484110f.0412220007.6a1893ca@posting.google.com...
| Quote: | Hello,
the DATA typ ist "shot int" type.
you wrote:
"At first glance I would make sure that the variables prueftest[],
prueftest2[ ] are aligned on 2*nx = 2*256 = 512"
why is nx=256, nx=NX=128, also variables prueftest(), and prueftest2()
have a size of SINE_TABLE_SIZE=256=2*NX=2*128
or do you mind something else?
in the example rfft will be not use #pragma DATA_SECTION,
but I will read about it.
I will see the example rfft one more time.
thanks
I wish you a merry Christmas
|
By TI's Definition, rfft(DATA x, nx, short scale)
nx is the length of the buffer passed to the rfft function, which in your
case you are calling it as:
| Quote: | rfft(prueftest2,SINE_TABLE_SIZE,scale);
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i.e. the nx parameter is SINE_TABLE_SIZE which as you have stated is 256.
That is why nx is 256 and that prueftest[ ] needs to be aligned on 2*256=
512 boundary.
Are you using the .align directive in your linker command file?
Look at ti's example, in one of the include files (.h) their variable x[] is
defined and the DATA_SECTION pragma is used.
-Shawn |
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