[avr-gcc-list] floating point calculations - How many cycles

[intiha Ho gai]

Hi,
I know this is a kinda elementary question, but i am not sure how to
calcuate the number of clock cycles on an Atmel 128L (7.3Mhz) would
the following line of code doing floating point multiplication take.

currTime = (uint32_t)(skew_*(double)currTime + offset_);//compensation
over here!!

here the currTime and offset are 32 bit integers, while the skew is a
floating point with value very close to zero (0.999987 therof).
If some one can tell me how to do this clacuation, I would be grateful.

Thank you.
Affan