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IQ math library include vs. IQmath.h include

Randy Carpenter
Prodigy 230 points
Other Parts Discussed in Thread: TMS320F28035

I'm building a project for a TMS320F28035 and trying to speed up the math calculations using the IQmath functions.  The _IQsmpy() , _IQ() , _IQabs(), and _IQmpyI32() functions all work with just the IQmath.h included, but the _IQdiv() function keeps giving me an error when I try to build the project with it being used in it.

 

Do I need to add the IQmath.lib  to the project or can I just use the IQmath.h?

  • 0
    Guru 20525 points

    Hello!

    It seems there is such solution. At the file IQmath.h you can see following:

    #ifndef GLOBAL_Q
    #define GLOBAL_Q (24)
    #endif

    ...........................................

    #if GLOBAL_Q == 24
    #define _IQdiv(A,B) (_IQ24div((A),(B)))
    #endif

    Therefore try using _IQ24div() insted _IQdiv(). Also you can use other variants of _IQdiv() according to your needs if you will redefine GLOBAL_Q appropriately.

    Regards,

    Igor

  • 0
    TI__Guru* 92780 points

    Randy Carpenter said:
    The _IQsmpy() , _IQ() , _IQabs(), and _IQmpyI32() functions all work with just the IQmath.h included,

    _IQ() is simply a multiplication and thus can be performed by the parser.  The definitions are in the .h file and no function is actually called.

    i.e.

    #if GLOBAL_Q == 29
    #define   _IQ(A)  _IQ29(A)
    #endif

    #define   _IQ29(A)      (long) ((A) * 536870912.0L)

    The rest of the functions you mention are built into the compiler so you don't need additional code (library).   IQabs() uses a function in the runtime support library.

    Randy Carpenter said:

    but the _IQdiv() function keeps giving me an error when I try to build the project with it being used in it.

     

    Do I need to add the IQmath.lib  to the project or can I just use the IQmath.h?

    Yes IQdiv() requires a function which is provided in the library - a library is a set of pre-compiled functions.  In order to use sin/cos/tan/div/etc you will need the lib to be linked into your project.

    -Lori

  • 0
    Guru 20525 points

    Hi!

    At http://processors.wiki.ti.com/index.php/C28x_Compiler_Error_and_Warning_Messages (Error: unresolved symbols remain....):

    For example, if your code had the statement c = IQdiv(a,b); but the IQmath library has not been included in the project, the symbol IQdiv will be flagged as undefined.

    Regards,

    Igor