K 10
svn:author
V 3
das
K 8
svn:date
V 27
2008-08-02T19:17:00.494332Z
K 7
svn:log
V 217
A few minor corrections, including some from bde:
- When y/x is huge, it's faster and more accurate to return pi/2
  instead of pi - pi/2.
- There's no need for 3 lines of bit fiddling to compute -z.
- Fix a comment.

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