Will it erroneous ??

Well, my processor if basically a dual core consist of C51 MPU code and DSP Compute Engine core. But i think the problem is independent of processor, and somehow related to the code generated by Keil. There are 2 WD Timers. One is hardware and one is 8051 s/w. I disabled both, so no issue with rebooting by WD timer reset.

The strange behavior i observed in above code snippet is, when i call the test() function as below, system is misbehaving:

void main(void) { unsigned char i;

   while(1) {
      for(i=0; i<8; i++) {
         magicString[i] += 1;
      }
      test(&magicString);   // Passing address
   }
}

void test(unsigned char const xdata* buffer) {...}

But if i called the test() as below in above code, the system works fine:

test((unsigned char xdata *)&magicString); //Casting
test(magicString); // W/o casting

Its hard time for me to understand whats wrong with passing address of magicString i.e. test(&magicString) ?

Can anybody explain me why the last 2 test() work fine and not the first.

Well, my processor if basically a dual core consist of C51 MPU code and DSP Compute Engine core. But i think the problem is independent of processor, and somehow related to the code generated by Keil. There are 2 WD Timers. One is hardware and one is 8051 s/w. I disabled both, so no issue with rebooting by WD timer reset.

The strange behavior i observed in above code snippet is, when i call the test() function as below, system is misbehaving:

void main(void) { unsigned char i;

   while(1) {
      for(i=0; i<8; i++) {
         magicString[i] += 1;
      }
      test(&magicString);   // Passing address
   }
}

void test(unsigned char const xdata* buffer) {...}

But if i called the test() as below in above code, the system works fine:

test((unsigned char xdata *)&magicString); //Casting
test(magicString); // W/o casting

Its hard time for me to understand whats wrong with passing address of magicString i.e. test(&magicString) ?

Can anybody explain me why the last 2 test() work fine and not the first.

Its hard time for me to understand whats wrong with passing address of magicString i.e. test(&magicString) ?

"&magicString" is not the address of the first element of the array magicString[]. That's where the error is.

What you actually want is "&magicString[0]" or just "magicString", which both are a pointer to the first element of magicString.

""&magicString" is not the address of the first element of the array magicString[]."

If it isn't, then what is it?

The types that they point to are different but the address should be same. That's my understanding anyhow. (I haven't got a copy of the C standard before you ask though!)

void test(unsigned char const xdata* buffer) { unsigned char j;
for (j=8; j>0; j--) { send(*buffer++); // another function }
}

Should you be able to increment a const pointer passed as a parameter to a function?

"buffer" is not const, given that declaration. It points to a const char, but is not itself const.

const is left-associative. (If there's nothing to its left, it will modify the thing to its right.)

Another way to look at it is that anything to the left of the * describes the type pointed to; anything to the right describes the pointer itself.

The types that they point to are different but the address should be same.

Yes, that's right. I had hoped the person who thought otherwise would realise this in the process of trying to answer the question.