This patch adds the float32_to_uint64() routine, which converts a
32-bit floating point number to an unsigned 64 bit number.

This contribution can be licensed under either the softfloat-2a or -2b
license.
Signed-off-by: NTom Musta <tommusta@gmail.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
[PMM: removed harmless but silly int64_t casts]
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NRichard Henderson <rth@twiddle.net>