Zig 0.17.0-dev (Split by item)

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sincosx

sincos.sincosx
pub fn sincosx(x: f80, r_sin: *f80, r_cos: *f80) callconv(.c) void

File

lib/compiler_rt/sincos.zig:195

Code

pub fn sincosx(x: f80, r_sin: *f80, r_cos: *f80) callconv(.c) void {
    const se = ld.signExponent(x) & 0x7fff;
    if (se == 0x7fff) {
        const result = x - x;
        r_sin.* = result;
        r_cos.* = result;
        return;
    }

    if (@abs(x) < trig.pi_4) {
        if (se < 0x3fff - math.floatMantissaBits(f80)) {
            // raise underflow if subnormal
            if (compiler_rt.want_float_exceptions and se == 0) {
                mem.doNotOptimizeAway(x * 0x1p-120);
            }
            r_sin.* = x;
            // raise inexact if x!=0
            r_cos.* = 1.0 + x;
            return;
        }
        r_sin.* = trig.sinx(x, 0.0, 0);
        r_cos.* = trig.cosx(x, 0.0);
        return;
    }

    var y: [2]f80 = undefined;
    const n = rem_pio2l(f80, x, &y);
    const s = trig.sinx(y[0], y[1], 1);
    const c = trig.cosx(y[0], y[1]);
    switch (n & 3) {
        0 => {
            r_sin.* = s;
            r_cos.* = c;
        },
        1 => {
            r_sin.* = c;
            r_cos.* = -s;
        },
        2 => {
            r_sin.* = -s;
            r_cos.* = -c;
        },
        else => {
            r_sin.* = -c;
            r_cos.* = s;
        },
    }
}