authorgravatar for hi@viri.moeviri <hi@viri.moe> 2022-04-07 01:24:46-06:00
committergravatar for hi@viri.moeviri <hi@viri.moe> 2022-04-07 02:38:28-06:00
loga2f5f0da5c21dd89834ec2b284ef2e7d2f5851a2
treee12e9b4215efeb0c4108c3589dab1f3c671e5e4f
parent289ba5dfc2dbd5f6f179c49e974b0332f16604a6
signaturelock-open Commit is signed but in an unrecognized format.

std.math.isFinite: make generic, support f80

1 files changed, 29 insertions(+), 45 deletions(-)

lib/std/math/isfinite.zig+29-45
......@@ -1,59 +1,43 @@
11const std = @import("../std.zig");
22const math = std.math;
33const expect = std.testing.expect;
4const maxInt = std.math.maxInt;
54
65/// Returns whether x is a finite value.
76pub fn isFinite(x: anytype) bool {
87 const T = @TypeOf(x);
9 switch (T) {
10 f16 => {
11 const bits = @bitCast(u16, x);
12 return bits & 0x7FFF < 0x7C00;
13 },
14 f32 => {
15 const bits = @bitCast(u32, x);
16 return bits & 0x7FFFFFFF < 0x7F800000;
17 },
18 f64 => {
19 const bits = @bitCast(u64, x);
20 return bits & (maxInt(u64) >> 1) < (0x7FF << 52);
21 },
22 f128 => {
23 const bits = @bitCast(u128, x);
24 return bits & (maxInt(u128) >> 1) < (0x7FFF << 112);
25 },
26 else => {
27 @compileError("isFinite not implemented for " ++ @typeName(T));
28 },
8 const TBits = std.meta.Int(.unsigned, @bitSizeOf(T));
9 if (@typeInfo(T) != .Float) {
10 @compileError("isFinite not implemented for " ++ @typeName(T));
2911 }
12 const exponent_bits = math.floatExponentBits(T);
13 const mantissa_bits = math.floatMantissaBits(T);
14 const all1s_exponent = ((1 << exponent_bits) - 1) << mantissa_bits;
15 const remove_sign = ~@as(TBits, 0) >> 1;
16 return @bitCast(TBits, x) & remove_sign < all1s_exponent;
3017}
3118
3219test "math.isFinite" {
33 try expect(isFinite(@as(f16, 0.0)));
34 try expect(isFinite(@as(f16, -0.0)));
35 try expect(isFinite(@as(f32, 0.0)));
36 try expect(isFinite(@as(f32, -0.0)));
37 try expect(isFinite(@as(f64, 0.0)));
38 try expect(isFinite(@as(f64, -0.0)));
39 try expect(isFinite(@as(f128, 0.0)));
40 try expect(isFinite(@as(f128, -0.0)));
20 // TODO remove when #11391 is resolved
21 if (@import("builtin").os.tag == .freebsd) return error.SkipZigTest;
4122
42 try expect(!isFinite(math.inf(f16)));
43 try expect(!isFinite(-math.inf(f16)));
44 try expect(!isFinite(math.inf(f32)));
45 try expect(!isFinite(-math.inf(f32)));
46 try expect(!isFinite(math.inf(f64)));
47 try expect(!isFinite(-math.inf(f64)));
48 try expect(!isFinite(math.inf(f128)));
49 try expect(!isFinite(-math.inf(f128)));
23 inline for ([_]type{ f16, f32, f64, f80, f128 }) |T| {
24 // normals
25 try expect(isFinite(@as(T, 1.0)));
26 try expect(isFinite(-@as(T, 1.0)));
5027
51 try expect(!isFinite(math.nan(f16)));
52 try expect(!isFinite(-math.nan(f16)));
53 try expect(!isFinite(math.nan(f32)));
54 try expect(!isFinite(-math.nan(f32)));
55 try expect(!isFinite(math.nan(f64)));
56 try expect(!isFinite(-math.nan(f64)));
57 try expect(!isFinite(math.nan(f128)));
58 try expect(!isFinite(-math.nan(f128)));
28 // zero & subnormals
29 try expect(isFinite(@as(T, 0.0)));
30 try expect(isFinite(@as(T, -0.0)));
31 try expect(isFinite(math.floatTrueMin(T)));
32
33 // other float limits
34 try expect(isFinite(math.floatMin(T)));
35 try expect(isFinite(math.floatMax(T)));
36
37 // inf & nan
38 try expect(!isFinite(math.inf(T)));
39 try expect(!isFinite(-math.inf(T)));
40 try expect(!isFinite(math.nan(T)));
41 try expect(!isFinite(-math.nan(T)));
42 }
5943}