There is no true double division on all amd cards.
Although on evergreen and newer cards you have native reduced accuracy reciprocal ( 1/x with lower 32 bits equal to 0 ). By adding few ( ~4-5 ) mad instruction you can get true accuracy reciprocal or ddiv.
On older cards (770) ddiv is simulated using int math ( if i remember correctly ) and results in about ~100 ops.
Of course you need card supporting doubles.