Some operations wouldn't make much sense with Float, for instance the 'complement' function. What should it return? Also note that bit manipulation functions could cover only a small window of the value range. So it could happen that x .|. y = x, even though y is nonzero. Also rotation would be a destructive operation.
Perhaps I can illustrate this with an example. It's very common with SSE code to interpret a float as both a mask and a number. You can exchange the two freely. For instance, in c-like pseudo code, you can write: float mask = myval == 0 ? 0x00000000 : 0xffffffff float temp = 5 / myval float result = mask .&. temp Which returns 0 or the result of 5 / myval. Each line above turns into a single sse instruction, and there are no branches. Bit wise operations on Floats should operate as if you had reinterpreted the Float as an unsigned integer. There are plenty of other examples of bit twiddling floats. Floats have a well defined bit representation (if a slightly complex one) so it's perfectly reasonable to be able to manipulate it. A complement operation on a float returns a float, and is well defined, if the output bit pattern is one you want. An alternative way to model this would be to provide ways to reinterpret a float as a word32, which helps enforce static typing. I don't know of any way of doing this in Haskell though. Does that make more sense? Thanks, Sam