Hi,
while rotating a byte ... to store the carry it is a little bit confusing!
Depend on what do you mean with "story". Here is an example how to do in ANSI C:

unsigned char a_byte, carry;

// ...
// here we need to do something like RLC a_byte
if (a_byte & 0x80)
{
  a_byte = (a_byte << 1) | (carry ? 1 : 0);
  carry = 1;
}
else
{
  a_byte = (a_byte << 1) | (carry ? 1 : 0);
  carry = 0;
}

Here I used unsigned char for carry flag. You may use bitfield (carry :1). With Keil you just need to read manual about how to use bit/sbit fields.
But as Andy already said: do not use REAL Carry Flag (PSW.7) because it is subject of change by compiler without notification you.

Good days!