1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
|
// Ported from musl, which is licensed under the MIT license:
// https://git.musl-libc.org/cgit/musl/tree/COPYRIGHT
//
// https://git.musl-libc.org/cgit/musl/tree/src/math/fabsf.c
// https://git.musl-libc.org/cgit/musl/tree/src/math/fabs.c
const std = @import("../std.zig");
const math = std.math;
const expect = std.testing.expect;
const maxInt = std.math.maxInt;
/// Returns the absolute value of x.
///
/// Special Cases:
/// - fabs(+-inf) = +inf
/// - fabs(nan) = nan
pub fn fabs(x: anytype) @TypeOf(x) {
const T = @TypeOf(x);
return switch (T) {
f16 => fabs16(x),
f32 => fabs32(x),
f64 => fabs64(x),
f128 => fabs128(x),
else => @compileError("fabs not implemented for " ++ @typeName(T)),
};
}
fn fabs16(x: f16) f16 {
var u = @bitCast(u16, x);
u &= 0x7FFF;
return @bitCast(f16, u);
}
fn fabs32(x: f32) f32 {
var u = @bitCast(u32, x);
u &= 0x7FFFFFFF;
return @bitCast(f32, u);
}
fn fabs64(x: f64) f64 {
var u = @bitCast(u64, x);
u &= maxInt(u64) >> 1;
return @bitCast(f64, u);
}
fn fabs128(x: f128) f128 {
var u = @bitCast(u128, x);
u &= maxInt(u128) >> 1;
return @bitCast(f128, u);
}
test "math.fabs" {
try expect(fabs(@as(f16, 1.0)) == fabs16(1.0));
try expect(fabs(@as(f32, 1.0)) == fabs32(1.0));
try expect(fabs(@as(f64, 1.0)) == fabs64(1.0));
try expect(fabs(@as(f128, 1.0)) == fabs128(1.0));
}
test "math.fabs16" {
try expect(fabs16(1.0) == 1.0);
try expect(fabs16(-1.0) == 1.0);
}
test "math.fabs32" {
try expect(fabs32(1.0) == 1.0);
try expect(fabs32(-1.0) == 1.0);
}
test "math.fabs64" {
try expect(fabs64(1.0) == 1.0);
try expect(fabs64(-1.0) == 1.0);
}
test "math.fabs128" {
try expect(fabs128(1.0) == 1.0);
try expect(fabs128(-1.0) == 1.0);
}
test "math.fabs16.special" {
try expect(math.isPositiveInf(fabs(math.inf(f16))));
try expect(math.isPositiveInf(fabs(-math.inf(f16))));
try expect(math.isNan(fabs(math.nan(f16))));
}
test "math.fabs32.special" {
try expect(math.isPositiveInf(fabs(math.inf(f32))));
try expect(math.isPositiveInf(fabs(-math.inf(f32))));
try expect(math.isNan(fabs(math.nan(f32))));
}
test "math.fabs64.special" {
try expect(math.isPositiveInf(fabs(math.inf(f64))));
try expect(math.isPositiveInf(fabs(-math.inf(f64))));
try expect(math.isNan(fabs(math.nan(f64))));
}
test "math.fabs128.special" {
try expect(math.isPositiveInf(fabs(math.inf(f128))));
try expect(math.isPositiveInf(fabs(-math.inf(f128))));
try expect(math.isNan(fabs(math.nan(f128))));
}
|
