diff --git a/core/math/math.odin b/core/math/math.odin index a5d86cffb..0d8873071 100644 --- a/core/math/math.odin +++ b/core/math/math.odin @@ -209,8 +209,9 @@ pow2_f64 :: proc(#any_int exp: int) -> (res: f64) { return transmute(f64)(u64(exp + F64_BIAS) << F64_SHIFT) case exp < -1075: // Underflow return f64(0) - case exp == -1075: // Underflow - return 0h00000000_00000001 + case exp == -1075: // Underflow. + // Note that pow(2, -1075) returns 0h1 on Windows and 0h0 on macOS & Linux. + return 0h00000000_00000000 case exp < -1022: // Denormal x := u64(exp + (F64_SHIFT + 1) + F64_BIAS) << F64_SHIFT return f64(1) / (1 << (F64_SHIFT + 1)) * transmute(f64)x diff --git a/tests/internal/test_pow b/tests/internal/test_pow new file mode 100644 index 000000000..00fb4a3d5 Binary files /dev/null and b/tests/internal/test_pow differ diff --git a/tests/internal/test_pow.odin b/tests/internal/test_pow.odin index b169e1361..3dfc44308 100644 --- a/tests/internal/test_pow.odin +++ b/tests/internal/test_pow.odin @@ -13,21 +13,27 @@ pow_test :: proc(t: ^testing.T) { v2 := math.pow2_f64(exp) _v1 := transmute(u64)v1 _v2 := transmute(u64)v2 - expect(t, _v1 == _v2, fmt.tprintf("Expected math.pow2_f64(%d) == math.pow(2, %d) (= %x), got %x", exp, exp, v1, v2)) + if exp == -1075 && ODIN_OS == .Windows { + // LLVM on Windows returns 0h00000000_00000001 for pow(2, -1075), + // unlike macOS and Linux where it returns 0h00000000_00000000 + // pow2_f64 returns the same float on all platforms because it isn't this stupid + _v1 = 0h00000000_00000000 + } + expect(t, _v1 == _v2, fmt.tprintf("Expected math.pow2_f64(%d) == math.pow(2, %d) (= %16x), got %16x", exp, exp, _v1, _v2)) } { v1 := math.pow(2, f32(exp)) v2 := math.pow2_f32(exp) _v1 := transmute(u32)v1 _v2 := transmute(u32)v2 - expect(t, _v1 == _v2, fmt.tprintf("Expected math.pow2_f32(%d) == math.pow(2, %d) (= %x), got %x", exp, exp, v1, v2)) + expect(t, _v1 == _v2, fmt.tprintf("Expected math.pow2_f32(%d) == math.pow(2, %d) (= %08x), got %08x", exp, exp, _v1, _v2)) } { v1 := math.pow(2, f16(exp)) v2 := math.pow2_f16(exp) _v1 := transmute(u16)v1 _v2 := transmute(u16)v2 - expect(t, _v1 == _v2, fmt.tprintf("Expected math.pow2_f16(%d) == math.pow(2, %d) (= %x), got %x", exp, exp, v1, v2)) + expect(t, _v1 == _v2, fmt.tprintf("Expected math.pow2_f16(%d) == math.pow(2, %d) (= %04x), got %04x", exp, exp, _v1, _v2)) } } }