Function as_sinpi_zero 

fn as_sinpi_zero<B: SinCosPiBackend>(x: f64, backend: &B) -> f64

Sinpi on range [0.0, 0.03515625]

Generated poly by Sollya:

d = [0, 0.03515625];

f_sin = sin(y*pi)/y;
Q = fpminimax(f_sin, [|0, 2, 4, 6, 8, 10|], [|107...|], d, relative, floating);

See ./notes/sinpi_zero_dd.sollya