Zig 0.17.0-dev (Split by item)

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sin

sin.sin

pub fn sin(x: f64) callconv(.c) f64

File

lib/compiler_rt/sin.zig:101

Code

pub fn sin(x: f64) callconv(.c) f64 {
    var ix = @as(u64, @bitCast(x)) >> 32;
    ix &= 0x7fffffff;

    // |x| ~< pi/4
    if (ix <= 0x3fe921fb) {
        if (ix < 0x3e500000) { // |x| < 2**-26
            // raise inexact if x != 0 and underflow if subnormal
            if (compiler_rt.want_float_exceptions) {
                if (ix < 0x00100000) {
                    mem.doNotOptimizeAway(x / 0x1p120);
                } else {
                    mem.doNotOptimizeAway(x + 0x1p120);
                }
            }
            return x;
        }
        return trig.sin(x, 0.0, 0);
    }

    // sin(Inf or NaN) is NaN
    if (ix >= 0x7ff00000) {
        return x - x;
    }

    var y: [2]f64 = undefined;
    const n = rem_pio2(x, &y);
    return switch (n & 3) {
        0 => trig.sin(y[0], y[1], 1),
        1 => trig.cos(y[0], y[1]),
        2 => -trig.sin(y[0], y[1], 1),
        else => -trig.cos(y[0], y[1]),
    };
}