When performing division or modulus operations involving variables of type unsigned long, the run-time library for these operations is called out without clearing the X flag.

2.1 Conditions

This problem may occur if the following four conditions are satisfied:

(1) A dividend is a variable.

(2) A divisor is a constant.

(3) Either or both of the dividend and divisor are of type unsigned long.

(4) A subscript of an array that takes an argument of type char is used in the conditional expression in an iteration statement immediately before a division or modulus operation.

Note: If the above conditions are all met, no problem may occur depending on the constructions of C source programs. If so, use your C compiler as it is.

2.2 Example

-------------------------------------------------------------
  void func(unsigned char ch, unsigned long *array)
  {
      unsigned long tmp;

      while( ch-- != 0 ){        /* Condition (4) */
          array[ch] = tmp / 10;     
                          /* Conditions (1), (2), and (3) */
      }
  }
-------------------------------------------------------------

Example:
-------------------------------------------------------------
  void func(unsigned int ch, unsigned long *array)
  {
      unsigned long tmp;

      while( ch-- != 0 ){
          array[ch] = tmp / 10;
      }
  }
-------------------------------------------------------------