zig/std/math/isnan.zig

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const math = @import("index.zig");
const assert = @import("../debug.zig").assert;
pub fn isNan(x: var) -> bool {
const T = @typeOf(x);
switch (T) {
f32 => {
const bits = @bitCast(u32, x);
bits & 0x7FFFFFFF > 0x7F800000
},
f64 => {
const bits = @bitCast(u64, x);
(bits & (@maxValue(u64) >> 1)) > (u64(0x7FF) << 52)
},
else => {
@compileError("isNan not implemented for " ++ @typeName(T));
},
}
}
test "isNan" {
assert(isNan(math.nan(f32)));
assert(isNan(math.nan(f64)));
assert(!isNan(f32(1.0)));
assert(!isNan(f64(1.0)));
}