mirror of
https://github.com/ziglang/zig.git
synced 2024-11-30 17:12:31 +00:00
75 lines
2.1 KiB
Zig
75 lines
2.1 KiB
Zig
// 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/copysignf.c
|
|
// https://git.musl-libc.org/cgit/musl/tree/src/math/copysign.c
|
|
|
|
const std = @import("../std.zig");
|
|
const math = std.math;
|
|
const expect = std.testing.expect;
|
|
const maxInt = std.math.maxInt;
|
|
|
|
/// Returns a value with the magnitude of x and the sign of y.
|
|
pub fn copysign(comptime T: type, x: T, y: T) T {
|
|
return switch (T) {
|
|
f16 => copysign16(x, y),
|
|
f32 => copysign32(x, y),
|
|
f64 => copysign64(x, y),
|
|
else => @compileError("copysign not implemented for " ++ @typeName(T)),
|
|
};
|
|
}
|
|
|
|
fn copysign16(x: f16, y: f16) f16 {
|
|
const ux = @bitCast(u16, x);
|
|
const uy = @bitCast(u16, y);
|
|
|
|
const h1 = ux & (maxInt(u16) / 2);
|
|
const h2 = uy & (@as(u16, 1) << 15);
|
|
return @bitCast(f16, h1 | h2);
|
|
}
|
|
|
|
fn copysign32(x: f32, y: f32) f32 {
|
|
const ux = @bitCast(u32, x);
|
|
const uy = @bitCast(u32, y);
|
|
|
|
const h1 = ux & (maxInt(u32) / 2);
|
|
const h2 = uy & (@as(u32, 1) << 31);
|
|
return @bitCast(f32, h1 | h2);
|
|
}
|
|
|
|
fn copysign64(x: f64, y: f64) f64 {
|
|
const ux = @bitCast(u64, x);
|
|
const uy = @bitCast(u64, y);
|
|
|
|
const h1 = ux & (maxInt(u64) / 2);
|
|
const h2 = uy & (@as(u64, 1) << 63);
|
|
return @bitCast(f64, h1 | h2);
|
|
}
|
|
|
|
test "math.copysign" {
|
|
expect(copysign(f16, 1.0, 1.0) == copysign16(1.0, 1.0));
|
|
expect(copysign(f32, 1.0, 1.0) == copysign32(1.0, 1.0));
|
|
expect(copysign(f64, 1.0, 1.0) == copysign64(1.0, 1.0));
|
|
}
|
|
|
|
test "math.copysign16" {
|
|
expect(copysign16(5.0, 1.0) == 5.0);
|
|
expect(copysign16(5.0, -1.0) == -5.0);
|
|
expect(copysign16(-5.0, -1.0) == -5.0);
|
|
expect(copysign16(-5.0, 1.0) == 5.0);
|
|
}
|
|
|
|
test "math.copysign32" {
|
|
expect(copysign32(5.0, 1.0) == 5.0);
|
|
expect(copysign32(5.0, -1.0) == -5.0);
|
|
expect(copysign32(-5.0, -1.0) == -5.0);
|
|
expect(copysign32(-5.0, 1.0) == 5.0);
|
|
}
|
|
|
|
test "math.copysign64" {
|
|
expect(copysign64(5.0, 1.0) == 5.0);
|
|
expect(copysign64(5.0, -1.0) == -5.0);
|
|
expect(copysign64(-5.0, -1.0) == -5.0);
|
|
expect(copysign64(-5.0, 1.0) == 5.0);
|
|
}
|