FAQ-0652 How can I save the ARM link register into a C++ variable


FAQ-0652 How can I save the ARM link register into a C++ variable

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Classification:	C++	Category:	Debugging
Created:	02/03/2000	Modified:	06/25/2001
Number:	FAQ-0652
Platform:	Not Applicable

Question:
I want to know where my function is being called from. How do I get the ARM link register into a C++ variable ?

Answer:
Here's a piece of code which does it, using the embedded assembler feature of GCC.

#include
#include

RTest test(_L("GETCH"));

GLDEF_C TInt E32Main()
{
// Must be before any function calls, including C++ constructors
TUint32 armLinkRegister;
asm("str lr, %0" : : "m" (armLinkRegister));

test.Start(_L("GETCH"));

test.Printf(_L("lr = %X\n"), armLinkRegister);

test.End();
return 0;
}