- Fixed uninitialized variables in default cases
- Fixed truncation of values to float with static_cast

Change-Id: I81f3a243e66eaeb24cd92646c6ef1ca6cb0de9ce
Reviewed-on: https://swiftshader-review.googlesource.com/5682Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>