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const LN2_HI : f32 = 6.9313812256e-01;
const LN2_LO : f32 = 9.0580006145e-06;
const LG1 : f32 = 0.66666662693;
const LG2 : f32 = 0.40000972152;
const LG3 : f32 = 0.28498786688;
const LG4 : f32 = 0.24279078841;
#[inline]
pub fn logf(mut x: f32) -> f32 {
let x1p25 = f32::from_bits(0x4c000000);
let mut ix = x.to_bits();
let mut k = 0i32;
if (ix < 0x00800000) || ((ix>>31) != 0) {
if ix<<1 == 0 {
return -1./(x*x);
}
if (ix>>31) != 0 {
return (x-x)/0.;
}
k -= 25;
x *= x1p25;
ix = x.to_bits();
} else if ix >= 0x7f800000 {
return x;
} else if ix == 0x3f800000 {
return 0.;
}
ix += 0x3f800000 - 0x3f3504f3;
k += ((ix>>23) as i32) - 0x7f;
ix = (ix & 0x007fffff) + 0x3f3504f3;
x = f32::from_bits(ix);
let f = x - 1.;
let s = f/(2. + f);
let z = s*s;
let w = z*z;
let t1 = w*(LG2+w*LG4);
let t2 = z*(LG1+w*LG3);
let r = t2 + t1;
let hfsq = 0.5*f*f;
let dk = k as f32;
s*(hfsq+r) + dk*LN2_LO - hfsq + f + dk*LN2_HI
}