fn acosBinary32(x: f32) f32x: f32107
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150fn acosBinary32(x: f32) f32 {
const pio2_hi: f32 = 1.5707962513e+00;
const pio2_lo: f32 = 7.5497894159e-08;
const hx: u32 = @bitCast(x);
const ix: u32 = hx & 0x7fff_ffff;
// |x| >= 1 or nan
if (ix >= 0x3f800000) {
if (ix == 0x3f800000) {
if (hx >> 31 != 0) {
return 2.0 * pio2_hi + 0x1.0p-120;
}
return 0.0;
}
return 0.0 / (x - x);
}
// |x| < 0.5
if (ix < 0x3f00_0000) {
// |x| < 2^(-26)
if (ix <= 0x3280_0000) {
return pio2_hi + 0x1.0p-120;
}
return pio2_hi - (x - (pio2_lo - x * rationalApproxBinary32(x * x)));
}
// x < -0.5
if (hx >> 31 != 0) {
const z = (1 + x) * 0.5;
const s = @sqrt(z);
const w = rationalApproxBinary32(z) * s - pio2_lo;
return 2.0 * (pio2_hi - (s + w));
}
// x > 0.5
const z = (1.0 - x) * 0.5;
const s = @sqrt(z);
const hs: u32 = @bitCast(s);
const df: f32 = @bitCast(hs & 0xffff_f000);
const c = (z - df * df) / (s + df);
const w = rationalApproxBinary32(z) * s + c;
return 2.0 * (df + w);
}