Thanks for your suggestion. but your suggestions are wrong. The actual problem
is number format. In my assembly code i used Q15 format.The Average value
is 0.225326. When you find the difference from the mean. For an example , the
sample value (-0.79421-0.225326) you will get -1.01951. Actually Q15 format
range is from -0.9 to 0.9. So to avoid this i convert Q15 to Q14 format then
solved the issue.
Regards
GJ
--- On Sun, 31/1/10, Mike Rosing wrote:
From: Mike Rosing
Subject: Re: [adsp] Variance Calculation Using Blackfin
To: "Dr Jayakumar Singaram"
Cc: a..., "Gnanavelu"
Date: Sunday, 31 January, 2010, 7:37 AM
What jk said is correct - in your C you have defined things as "float",
but in assembler you are using ints. Look at the assembly from the
C compiler (-S switch or click on something that will generate it).
To get different results for both C and assembler, look into setting up
the "saturation mode". And for both integer and fractional modes.
You will get a lot of different answers - all of them correct :-)
Patience, persistence, truth,
Dr. mike
On Sat, 30 Jan 2010, Dr Jayakumar Singaram wrote:
> Dear Velu san,
> Blackfin for simple people and simple applications (
!!!!! dont take it as it is... but hint is the following).
>
> Blackfin will be using ACC to store sum value that
comes out of each iteration of for loop. I think ACC itself getting overflow
mode when you go for 32 or 1024 samples based for loop. If we assume this is
true then we can find N number of solutions for the same.
>
> most primitive... .
> just make many ( needful number) 16 samples loop to
solve 32 or 1024. In this, mem will be used as a ACC at the end for loop ( 16
times) and add them or divide them and add them. I mean you can divide each
loop by 16 to get value and add result... this will help. If you want c code i
can write but i want you to write and enjoy the joy working with primitive
computing machines.
>
>
> Advanced hint.
> Select fractional format such that ACC does not
overflow ( this will be data dependent and you need to know more details about
your data array). Without details about data array it is not east to decide
format.
>
> Have a nice week end.
>
> Kind Regards
> jk
>
> ----- Original Message -----
> From: Gnanavelu
> To: adsp@yahoogroups. com
> Sent: Saturday, January 30, 2010 9:18 AM
> Subject: [adsp] Variance Calculation Using
Blackfin
>
>
>
> Hi
> I am determining the Variance in Blackfin DSP
using assembly language.
> I compared with the c code under following
cases
>
> 1. 8 samples
> 2. 16 samples
> 3. 32 samples
> 4. 1024 samples.
>
> I got correct result under case 1 and case 2.
But i am not getting correct result under case 3 and 4. C and Assembly codes
are below. Also shared at
> printf("Variance Value Using Assembly =
%f\n", VarianceFloat) ;
>
> }
>
>
>
>
>
> .section/code program;
> .global __VarianceCalculate ;
>
> __VarianceCalculate :
> I0 = R0; // Signal
> I1 = R1; // Variance
Address
> LC0 = R2; // Buffer
Length
> LC1 = R2;
> R3 = 0;
> R4 = 0;
> LSETUP(_AverageStar
t,_AverageEnd) LC0;
> _AverageStart:
> R3.H = W[ I0 ++ ];
> R3 = R3>>>5;
> _AverageEnd:
> R4 = R4 + R3; // Mean Value
at R4 register
> I0 = R0;
> R3 = 0;
> A0 = 0;
>
> LSETUP(_VarianceSta
rt,_VarianceEnd) LC1;
> _VarianceStart:
> R3.H = W[ I0 ++ ];
> R2 = R3 - R4;
> _VarianceEnd:
> A0 +=R2.H*R2.H;
> A0 = A0>>>5;
> R0 = A0;
> W[ I1 ] = R0.H;
> RTS;
> NOP;
> __VarianceCalculate .end:
>
>
>
>
> Regards
> Gnanavel
>
Reply by Mike Rosing●January 30, 20102010-01-30
What jk said is correct - in your C you have defined things as "float",
but in assembler you are using ints. Look at the assembly from the
C compiler (-S switch or click on something that will generate it).
To get different results for both C and assembler, look into setting up
the "saturation mode". And for both integer and fractional modes.
You will get a lot of different answers - all of them correct :-)
Patience, persistence, truth,
Dr. mike
On Sat, 30 Jan 2010, Dr Jayakumar Singaram wrote:
> Dear Velu san,
> Blackfin for simple people and simple applications ( !!!!! dont take it as it
is... but hint is the following).
>
> Blackfin will be using ACC to store sum value that comes out of each iteration
of for loop. I think ACC itself getting overflow mode when you go for 32 or
1024 samples based for loop. If we assume this is true then we can find N number
of solutions for the same.
>
> most primitive....
> just make many ( needful number) 16 samples loop to solve 32 or 1024. In this,
mem will be used as a ACC at the end for loop ( 16 times) and add them or
divide them and add them. I mean you can divide each loop by 16 to get value and
add result... this will help. If you want c code i can write but i want you to
write and enjoy the joy working with primitive computing machines.
> Advanced hint.
> Select fractional format such that ACC does not overflow ( this will be data
dependent and you need to know more details about your data array). Without
details about data array it is not east to decide format.
>
> Have a nice week end.
>
> Kind Regards
> jk
>
> ----- Original Message -----
> From: Gnanavelu
> To: a...
> Sent: Saturday, January 30, 2010 9:18 AM
> Subject: [adsp] Variance Calculation Using Blackfin
>
> Hi
> I am determining the Variance in Blackfin DSP using assembly
language.
> I compared with the c code under following cases
>
> 1. 8 samples
> 2. 16 samples
> 3. 32 samples
> 4. 1024 samples.
>
> I got correct result under case 1 and case 2. But i am not getting
correct result under case 3 and 4. C and Assembly codes are below. Also shared
at
> http://www.4shared.com/file/210861924/d79c05b4/VarianceCalc.html
> Can somebody tell me where is the wrong.
>
> #include
> #include
> #include #define MAX_SIZE 32//1024
>
> float InputData[MAX_SIZE] ={
> 0.25005,0.59361,0.16858,0.66254,
> 0.73142,0.14195,-0.42078,-0.21316,
> -0.28167,0.68526,0.76273,0.35498,
> 0.5977,0.17204,0.24829,0.052611
> -0.1665,-0.79421,0.062438,0.094364,
> 0.43401,-0.011778,0.17192,0.98137,
> 0.54351,0.91544,-0.97341,0.12246,
> 0.0055164,-0.014214,0.97314,0.36023
> /* 0.44436,-0.43146,0.20522,0.47057,
> 0.6912,0.44631,0.41747,0.23028,
> -0.86039,0.94002,-0.31636,0.97059,
> -0.88821,0.82206,0.64462,0.835,
> 0.047385,0.59136,0.99241,0.25644,
> 0.10618,0.24282,0.32284,0.55811,
> -0.29633,0.70868,-0.43582,-0.84618,
> 0.24908,-0.82105,-0.82567,0.25509,
> 0.73364,0.66384,0.78594,0.7538,
> 0.99733,0.7704,0.88123,-0.35055,
> 0.80984,-0.97032,0.23707,
>
> */
> // #include "RandomSig.dat"
> };
>
> short InputDataFr16[MAX_SIZE];
> short VarianceVal;
>
> void main(){
> short i;
> float Sum=0.0;
> float MeanValue;
> float SquareDiff;
> float M;
> float VarianceFloat,VarianceSum=0.0;
> for (i=0;i
> InputDataFr16[i] = float_to_fr16(InputData[i]);
> }
>
> for(i=0;i
> Sum += InputData[i];
> }
>
> M = (float)MAX_SIZE;
> MeanValue = Sum/M;
> printf( " Average Using C is %f\n",MeanValue);
>
> for(i=0;i
> SquareDiff = pow((InputData[i]-MeanValue),2.0);
> // printf("%f\n",SquareDiff);
> VarianceSum += SquareDiff;
> }
> VarianceSum = VarianceSum/M;
> printf("Variance is %f\n", VarianceSum);
> _VarianceCalculate(&InputDataFr16[0],&VarianceVal,MAX_SIZE);
> VarianceFloat = fr16_to_float(VarianceVal);
> printf("Variance Value Using Assembly = %f\n", VarianceFloat);
>
> }
>
> .section/code program;
> .global __VarianceCalculate;
>
> __VarianceCalculate:
> I0 = R0; // Signal
> I1 = R1; // Variance Address
> LC0 = R2; // Buffer Length
> LC1 = R2;
> R3 = 0;
> R4 = 0;
> LSETUP(_AverageStart,_AverageEnd) LC0;
> _AverageStart:
> R3.H = W[ I0 ++ ];
> R3 = R3>>>5;
> _AverageEnd:
> R4 = R4 + R3; // Mean Value at R4 register
> I0 = R0;
> R3 = 0;
> A0 = 0;
>
> LSETUP(_VarianceStart,_VarianceEnd) LC1;
> _VarianceStart:
> R3.H = W[ I0 ++ ];
> R2 = R3 - R4;
> _VarianceEnd:
> A0 +=R2.H*R2.H;
> A0 = A0>>>5;
> R0 = A0;
> W[ I1 ] = R0.H;
> RTS;
> NOP;
> __VarianceCalculate.end:
> Regards
> Gnanavel
>
> ------
> Your Mail works best with the New Yahoo Optimized IE8. Get it NOW!.
Reply by Dr Jayakumar Singaram●January 30, 20102010-01-30
Dear Velu san,
Blackfin for simple people and simple applications ( !!!!! dont take it as it
is... but hint is the following).
Blackfin will be using ACC to store sum value that comes out of each iteration
of for loop. I think ACC itself getting overflow mode when you go for 32 or
1024 samples based for loop. If we assume this is true then we can find N number
of solutions for the same.
most primitive....
just make many ( needful number) 16 samples loop to solve 32 or 1024. In this,
mem will be used as a ACC at the end for loop ( 16 times) and add them or
divide them and add them. I mean you can divide each loop by 16 to get value and
add result... this will help. If you want c code i can write but i want you to
write and enjoy the joy working with primitive computing machines.
Advanced hint.
Select fractional format such that ACC does not overflow ( this will be data
dependent and you need to know more details about your data array). Without
details about data array it is not east to decide format.
Have a nice week end.
Kind Regards
jk
----- Original Message -----
From: Gnanavelu
To: a...
Sent: Saturday, January 30, 2010 9:18 AM
Subject: [adsp] Variance Calculation Using Blackfin
Hi
I am determining the Variance in Blackfin DSP using assembly language.
I compared with the c code under following cases