How to byte swap an IEEE Float?

[Björn <ssh9614@hotmail.com>]

I need to read some float values from file that have been written in
big-endian byte order from a c-program. The simple swapping procedure
that I have just interchanges the byte order of type IEEE_Float_32 to
get little-endian. The problem is that for some values (eg. 33.229000)
it is a "NaN" when doing IEEE_Float_32'Read and I get a constraint
error (invalid data) from stream_io when the value is read. How do I
get around this?

Thanks
Björn