| ... | ... | @@ -5,64 +5,19 @@ const expect = std.testing.expect; |
| 5 | 5 | /// Returns whether x is negative or negative 0. |
| 6 | 6 | pub fn signbit(x: anytype) bool { |
| 7 | 7 | const T = @TypeOf(x); |
| 8 | | return switch (T) { |
| 9 | | f16 => signbit16(x), |
| 10 | | f32 => signbit32(x), |
| 11 | | f64 => signbit64(x), |
| 12 | | f80 => signbit80(x), |
| 13 | | f128 => signbit128(x), |
| 14 | | else => @compileError("signbit not implemented for " ++ @typeName(T)), |
| 15 | | }; |
| 16 | | } |
| 17 | | |
| 18 | | fn signbit16(x: f16) bool { |
| 19 | | const bits = @bitCast(u16, x); |
| 20 | | return bits >> 15 != 0; |
| 21 | | } |
| 22 | | |
| 23 | | fn signbit32(x: f32) bool { |
| 24 | | const bits = @bitCast(u32, x); |
| 25 | | return bits >> 31 != 0; |
| 26 | | } |
| 27 | | |
| 28 | | fn signbit64(x: f64) bool { |
| 29 | | const bits = @bitCast(u64, x); |
| 30 | | return bits >> 63 != 0; |
| 31 | | } |
| 32 | | |
| 33 | | fn signbit80(x: f80) bool { |
| 34 | | const bits = @bitCast(u80, x); |
| 35 | | return bits >> 79 != 0; |
| 36 | | } |
| 37 | | |
| 38 | | fn signbit128(x: f128) bool { |
| 39 | | const bits = @bitCast(u128, x); |
| 40 | | return bits >> 127 != 0; |
| 8 | const TBits = std.meta.Int(.unsigned, @typeInfo(T).Float.bits); |
| 9 | return @bitCast(TBits, x) >> (@bitSizeOf(T) - 1) != 0; |
| 41 | 10 | } |
| 42 | 11 | |
| 43 | 12 | test "math.signbit" { |
| 44 | | try expect(signbit(@as(f16, 4.0)) == signbit16(4.0)); |
| 45 | | try expect(signbit(@as(f32, 4.0)) == signbit32(4.0)); |
| 46 | | try expect(signbit(@as(f64, 4.0)) == signbit64(4.0)); |
| 47 | | try expect(signbit(@as(f128, 4.0)) == signbit128(4.0)); |
| 48 | | } |
| 49 | | |
| 50 | | test "math.signbit16" { |
| 51 | | try expect(!signbit16(4.0)); |
| 52 | | try expect(signbit16(-3.0)); |
| 53 | | } |
| 54 | | |
| 55 | | test "math.signbit32" { |
| 56 | | try expect(!signbit32(4.0)); |
| 57 | | try expect(signbit32(-3.0)); |
| 58 | | } |
| 59 | | |
| 60 | | test "math.signbit64" { |
| 61 | | try expect(!signbit64(4.0)); |
| 62 | | try expect(signbit64(-3.0)); |
| 63 | | } |
| 64 | | |
| 65 | | test "math.signbit128" { |
| 66 | | try expect(!signbit128(4.0)); |
| 67 | | try expect(signbit128(-3.0)); |
| 13 | inline for ([_]type{ f16, f32, f64, f80, f128 }) |T| { |
| 14 | try expect(!signbit(@as(T, 0.0))); |
| 15 | try expect(!signbit(@as(T, 1.0))); |
| 16 | try expect(signbit(@as(T, -2.0))); |
| 17 | try expect(signbit(@as(T, -0.0))); |
| 18 | try expect(!signbit(math.inf(T))); |
| 19 | try expect(signbit(-math.inf(T))); |
| 20 | try expect(!signbit(math.nan(T))); |
| 21 | try expect(signbit(-math.nan(T))); |
| 22 | } |
| 68 | 23 | } |
alice <hi@dnydxn.moe> 2022-05-17 21:41:57+01:00