Thread: requesting a logic for mask calculation

Hi Guys,
I have wrote a small logic below which will calculate a value called MASK via which I can calculate the starting and ending number
This logic works fine if A = 0x14000000 B = 0x14000064

Code:

void main()
{
	unsigned long ulStartVal = 0x14000000;
	unsigned long ulEndVal = 0x14000064;
	unsigned long ulMask;
	unsigned long ulTempVal;
	// Calculate mask
	ulMask = ~((ulStartVal) ^ (ulEndVal));
	/* This step is kindoff mandatory startval AND operation with mask must give 
	the value of startval again (value of ulTempVal and ulStartVal must be same) */
	ulTempVal = ulStartVal & ulMask;
	printf("%x %x",ulTempVal, ulMask);
	//Endval calculation with startval and mask
	ulEndVal  = ~((ulTempVal) ^ (ulMask));
	printf("%x",ulEndVal);
}

But the above logic doesn't work fine if A = 0x1400000A B = 0x14000064 means if the value of A has last 8 bits set. C code or pseudo code or any suggestion on logic change is very much welcome.

its used to store starting ip address and derive ending ip address just with the help of mask..

This is as per configuration. Once a starting and ending IP address is given we need to store starting address ID and mask with the help of starting ID and mask calculate starting IP address and with the help of starting IP address and mask we need to calculate ending IP address