Modified addresses after single stepping a subroutine?

[User8541]

Hi,

I got a problem while debugging a program. I reduced the source code to a small sample which behaves as the big one.
Then I set up a new project ('File' -> 'new' -> 'DAVE project' -> 'DAVE CE Project' without any apps) and expanded main.c by some lines of code.

source code:

#include //Declarations from DAVE3 Code Generation (includes SFR declaration)

void func_1(void)
{
int a;
int b;
int c;

a = 4;
b = 5;
c= a * b;

if (c == c)
{
//
}
}


int main(void)
{
// status_t status; // Declaration of return variable for DAVE3 APIs (toggle comment if required)
char aaa;
char data_str1[] = {"HELLO WORLD\n"};
char data_str2[] = {"Dies ist noch ein Teststring\n"};


DAVE_Init(); // Initialization of DAVE Apps

func_1();
// ========================================================================
// ab hier sind die Variablen data_str1 und data_str2 nicht mehr erreichbar
// ========================================================================
aaa = data_str1[3];

aaa = data_str2[5];

if(aaa == aaa)
{
//
}

while(1)
{

}
return 0;
}


A breakpoint is set and activated in main() before executing func_1(). Execution is started with F8 and stops at breakpoint.
The addresses of data_str1 and data_str2 are 0x200007e0 and 0x200007c0 (Dave_3_1_10_DebugError_a.png) After stepping through func_1 with single steps (F5) and returning to main, the addreses have changed and are out of bounds: 0x1079e100 and 0x1079e0e0 (Dave_3_1_10_DebugError_b.png)
This problem does not occur if I step over func_1 (F6).

Where is the a bug in my sample program? Or is it a bug in DAVE3?


Version of DAVE 3 is: 3.1.10, Installer build : 2014-02-26
Hardware: "XMC4500-E144x1024 AA"
Debugger: SEGGER J-Link GDB Server V4.80f

Thanks in advance
Rudi

PS At the moment I cannot upload some screenshots

[User8541]

Hi,
here are the pictures referred to ...


Best regards,
Rudi

[#3]

You're initialising the strings wrong.

This: {"HELLO WORLD\n"};
Has the following type: const char ** const
I.e. an array of pointers to const char arrays.

This:
char data_str1[] = "HELLO WORLD\n";
Would work as expected.

[User8541]

Hi kamikaze,
nice idea, but DAVE3 is not fond of it. The address of the string is changed again.

I tried several ways to define strings and found a workaround (see data_str3):

#include 			//Declarations from DAVE3 Code Generation (includes SFR declaration)

void func_1(void)
{
int a;
int b;
int c;

	a = 4;
	b = 5;
	c= a * b;

	if (c == c)
	{
		//
	}
}



int main(void)
{
//	status_t status;		// Declaration of return variable for DAVE3 APIs (toggle comment if required)
char aaa;
char data_str1[] = "HELLO WORLD\n";
const char data_str2[] = "Dies ist noch ein Teststring\n";
const char data_str3[] = {'D', 'A', 'V', 'E', '3', '\n', '\0'};  // workaround for DAVE3 
const char data_str4[6] = "12345";


	DAVE_Init();			// Initialization of DAVE Apps

	func_1();
	// =========================================================================================================
	// since here variables data_str1, data_str2, data_str4 not reachable after single stepping through func_1()
	// =========================================================================================================
	aaa = data_str1[3];
	aaa = data_str2[5];
	aaa = data_str3[3];
	aaa = data_str4[3];

	if(aaa == aaa)
	{
		//
	}

	while(1)
	{

	}
	return 0;
}

It takes some more typing but DAVE3 does not destroy pointer to strings defined like data_str3 after single stepping subroutines.

Best regards,
Rudi

[#5]

Did you try:

const char * const data_str4 = "12345";

That should be exactly the same as:
const char data_str4[6] = "12345";

or:
const char data_str4[] = "12345";

or:
const char data_str4[] = {'1', '2', '3', '4', '5', 0};

They should all be equivalent. If they don't, at least logically, do the same, I'd expect that to be in violation of the standard.

[gwang]

Hi Rudi,

I recommend you to use iSystem debugger, then the problem will be resolved. Here is the documentation how to install iSystem in DAVE3:

http://www.infineon.com/dgdlc/en?dcId=8a8181663431cb50013431cb500b0000&downloadTitle=winIDEA_open_DA...

Alternatively, you can define the three variables as global variables like:

char aaa;
char data_str1[] = {"HELLO WORLD\n"};
char data_str2[] = {"Dies ist noch ein Teststring\n"};

int main(void)
{

}

Then, you can also user IFX GDB and Tasking debugger to step into func_1().

Best regards

Guangyu

[#7]

Hi,

You can try to upgrade the Segger J-Link to v4.9e…

Best regards,
Sophia

[User8541]

Hi Sophia,

Update to Segger J-Link to v4.9e was helpfully. Addresses stuck as expected.

Best regards,
Rudi