vec_ctd: Vector Convert to Double

d = vec_ctd(a, b)
Converts the type of each element in a from integer to floating-point double precision and divides the result by 2 to the power of b.
Note: Current BFP rounding mode is used on the conversion.
Table 1. Vector Convert to Double
d a b
vector double vector signed long long 0 - 31
vector unsigned long long