2017-12-24 11:08:53 +08:00
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const std = @import("../index.zig");
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const math = std.math;
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2019-02-09 07:18:47 +08:00
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const expect = std.testing.expect;
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2018-10-27 02:59:58 +08:00
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const maxInt = std.math.maxInt;
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2017-06-16 16:26:10 +08:00
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2018-01-25 17:10:11 +08:00
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pub fn isNan(x: var) bool {
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2017-06-16 16:26:10 +08:00
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const T = @typeOf(x);
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switch (T) {
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2018-06-30 07:44:54 +08:00
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f16 => {
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const bits = @bitCast(u16, x);
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return (bits & 0x7fff) > 0x7c00;
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},
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2017-06-16 16:26:10 +08:00
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f32 => {
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const bits = @bitCast(u32, x);
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2017-12-22 13:50:30 +08:00
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return bits & 0x7FFFFFFF > 0x7F800000;
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2017-06-16 16:26:10 +08:00
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},
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f64 => {
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const bits = @bitCast(u64, x);
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2018-10-27 02:59:58 +08:00
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return (bits & (maxInt(u64) >> 1)) > (u64(0x7FF) << 52);
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2017-06-16 16:26:10 +08:00
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},
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else => {
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@compileError("isNan not implemented for " ++ @typeName(T));
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},
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}
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}
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2018-05-27 02:57:53 +08:00
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/// Note: A signalling nan is identical to a standard nan right now but may have a different bit
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/// representation in the future when required.
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2018-01-25 17:10:11 +08:00
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pub fn isSignalNan(x: var) bool {
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2017-12-22 13:50:30 +08:00
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return isNan(x);
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2017-06-20 19:01:04 +08:00
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}
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2017-06-20 02:36:33 +08:00
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test "math.isNan" {
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2019-02-09 07:18:47 +08:00
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expect(isNan(math.nan(f16)));
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expect(isNan(math.nan(f32)));
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expect(isNan(math.nan(f64)));
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expect(!isNan(f16(1.0)));
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expect(!isNan(f32(1.0)));
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expect(!isNan(f64(1.0)));
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2017-06-16 16:26:10 +08:00
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}
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