Zig 0.17.0-dev (Split by item)

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atanh_64

atanh.atanh_64

fn atanh_64(x: f64) f64

File

lib/std/math/atanh.zig:58

Code

fn atanh_64(x: f64) f64 {
    const u: u64 = @bitCast(x);
    const e = (u >> 52) & 0x7FF;
    const s = u >> 63;

    var y: f64 = @bitCast(u & (maxInt(u64) >> 1)); // |x|

    if (y == 1.0) {
        return math.copysign(math.inf(f64), x);
    }

    if (e < 0x3FF - 1) {
        if (e < 0x3FF - 32) {
            // underflow
            if (e == 0) {
                mem.doNotOptimizeAway(@as(f32, @floatCast(y)));
            }
        }
        // |x| < 0.5
        else {
            y = 0.5 * math.log1p(2 * y + 2 * y * y / (1 - y));
        }
    } else {
        y = 0.5 * math.log1p(2 * (y / (1 - y)));
    }

    return if (s != 0) -y else y;
}