//-----------------------------------------------------------------------------
// currentToPower(u16 *power, u16 current)
//-----------------------------------------------------------------------------
// Function calculates the heater power corresponding to the current flowing
// through it.
//
// Parameters:
// *power - pointer to power output variable [mW]
// current - heater current input variable [mA * 2^4]
//-----------------------------------------------------------------------------
void currentToPower(u16 *power, u16 current)
{
    static u32 temp;
    // Current is in 10.4 fixed-point format.
    // Square the current.
    // One of the factors needs to be cast as u32 to yield a u32 result.
    temp = (u32)current * current;

    // The result of the multiplication is 20.8 fixed-point.
    // Clip the 8 LSB to get whole mA^2 value.
    // This is temp = temp>>8, but Keil is stupid.
    *(((u8 *) &temp)+3) = *(((u8 *) &temp)+2);
    *(((u8 *) &temp)+2) = *(((u8 *) &temp)+1);
    *(((u8 *) &temp)+1) = *((u8 *) &temp);
    *((u8 *) &temp) = 0;

    // Multiply by heater resistance.
    // Rheat is in 6.6 fixed-point format, scaled by 1.024 (!NOT 1024!).
    temp *= RHEAT;

    // Result is in uW in 26.6 fixed-point format.
    // Clip the bottom 6 bits to get a whole value plus
    // 10 additional bits to convert directly to mW.
    // 16 LSB total are clipped from the above result.
    // This is the reason for having Rheat scaled by 1.024 earlier.
    *power = *((u16 *) &temp);
}