How to reduce computation time of F2812

Hi, Gautam

How to use IQMath Library? Besides, the calculation process only includes shift, plus and multiply, no other complex instruction. Does these also affect the time costing?

He, Siyu

Hi Siyu,

IQMath lib is very effective. It reduces the computation time like anything for example:

 while using IQNmpy the cycles reduced to 8-9 cycles!

Please check the page number 29 for the cycles consumed for all the instructions.

5023.iQMath Library.pdf

Regards,

Gautam

Hi Gautam,

Thanks for your information, I will try the lib and tell you what is going on my side.

He, Siyu

Sure keep me posted!

Hi Gautam,

I don't know how to do with the linker file come with the iQMathLib.h. I tried to incorporate the 2812_IQmath_lnk.cmd with my SRAM.cmd, but I still can not make it.

Would you please help me with this problem?

I tried to build my project with my orignal SRAM.cmd and iQmathLib.h included, the error of compilation shows that identifier "_iq" is undefined.

He,Siyu

Hi Siyu,

No need of any linker file. The regular Ram/Flash based linker file is enough for including IQMath.h header file. Please check for the include path in project properties. It has to include IQmath folder address in Control suite.

Regards,

Gautam

Gautam,

Do I need to add boot ROM symbol library(2802x_IQmath_BootROMSymbols.lib? or 2803x_IQmath_BootROMSymbols.lib?) and IQmath.lib to my project? I already put the IQmathLib.h in my project file.

He, Siyu

Siyu,

You'll have to include "C:\ti\controlSUITE\libs\math\IQmath\v160\lib" path in you project -> properties -> linker -> include

Thats it. Use a normal RAM/Flash cmd file that you've been using for other codes.

Regards,

Gautam

Gautam,

The IQmathLib.h is already in the folder of Include under my project. And also I add the path using Project->Build Options->Linker->Libraries, in the dialog of Incl.Libraries. But the compilation fails due to the same reason. The information is "DSP28_Globalvariable.h", line 23: error: identifier "_iq" is undefined". In this .h file, I defined

extern _iq IL;

I forgot to mention that I am using CCS.3.3

Ohk, I've never used this library with CCS 3.3 but it should work fine. Please check with the way you're implementing the _iq functions.

The only doc I referred while implementing this library is the one already attached. There's no other complications; just check with the implementation part.

Regards,

Gautam

Alright, I will try to follow the proccedure on the doc and let you know the results.

What versioin of CCS are you using?

He, Siyu

Mine is the latest, fully updated CCS 5.x

Gautam,

I need to do calcualtion in ISR, it seems like _iq  variables defined in main() can not be recognized in ISR. Then I tried to define _iq variables as gloable variables as extern. The compilation shows error "_iq" is undefined.

He, Siyu

Hi Siyu,

I'm really amazed! Yes for ISR declaring iq variables is a must. Secondly //"_iq" is undefined.// such kind of errors occur only if the library is not properly linked with the project. Did you go through the library?

Regards,

Gautam

Hi Gautam,

What do you mean by go through? I already added the both IQmath.lib and 2802x_IQmath_BootRomsymbols.lib into my projec.

He, Siyu

Lot of confusion Siyu, I'm shifting to the other post of yours. I guess you've got the answer for this post " How to reduce computation time of F2812"! Please close this post...

Regards,

Gautam

I am still trying to figure out why normal instructions, like right shift >>4, take so long. I think right shift and value assignment should just take 1 or 2 cpu cycle.

He, Siyu

Yes I agree with you Siyu but even I faced with the same issue. So I'd to shift to this library, later when I started using FPU F28335; there was no need of any library :)

Regards,

Gautam

Hi Gautam,

You are right. I just read a tutorial and noticed that computation of floating-point data is very time consuming on fix-point device like F2812, I should use IQmath libray.

Thanks for your information.

He, Siyu