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TMS320F28075: Reading IFR getting a warning

Brian Wang0
Expert 5390 points
Part Number: TMS320F28075


Champs,

My customer is reading back IFR via the follow function for diagnostic. But we are getting a warning. Anything need to be done to take care of this warning?

Thanks,

Brian

  • 0
    TI__Guru* 81500 points

    Brian,

    While the IFR will be stored in the AL register,  believe you still need to inform the compiler that funIFR will take on this value(even if we know it does).  Can you try something like the below for the funIFR() function:

    __asm(" .def _funIFR\n"
          " .global  _funIFR\n"
          "_funIFR:\n"
          " PUSH IFR\n"
          " POP AL\n"
          " LRETR\n");

    Best,

    Matthew

  • 0
    Guru 92251 points
    Brian Wang0 said:
    My customer is reading back IFR via the follow function for diagnostic.

    Section 6.5.2 The __cregister Keyword of  TMS320C28x Optimizing C/C++ Compiler v21.6.0.LTS User’s Guide explains how IFR can be accessed via the __cregister keyword, and has the following example code:

    extern cregister volatile unsigned int IFR;
extern cregister volatile unsigned int IER;
extern int x;
main()
{
 IER = x;
 IER |= 0x100;
 printf("IER = %x\n", IER);
 IFR &= 0x100;
 IFR |= 0x100;

    I.e. should be able to try the above rather than the funIFR function.

    I haven't tested this.

  • 0 in reply to Chester Gillon
    TI__Guru* 81500 points

    Chester,

    Thanks for bringing this up/showing this.  I had been looking in Section 7.6 in the assembly intrinsics and surprised we didn't have what you've posted above so I went the brute force route.

    I agree your method is cleaner, avoids any potential disruption of the C generated asm, and is proven! 

    Brian,

    I'd recommend your customer use the method Chester pointed out.

    Best,

    Matthew