I believe the error should be (roughly) ~ size of f.p. interval at 1 * pi ~ pi* 2^(-32/64), i.e. barely representable. Number of steps would be ~ 1/(error^2) ~

I believe the error should be (roughly) ~ size of f.p. interval at 1 * pi ~ pi* 2^(-32/64), i.e. barely representable. Number of steps would be ~ 1/(error^2) ~ 2^(2* 32/64). Even giving 50% probability at the line the result would be minutely biased because of many other things involving the discreteness of the floating point arithmetic. A less biased version would have to maybe increase the resolution around the boundary as number of steps progresses.