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d29871977f
We already have a LICENSE file that covers the Zig Standard Library. We no longer need to remind everyone that the license is MIT in every single file. Previously this was introduced to clarify the situation for a fork of Zig that made Zig's LICENSE file harder to find, and replaced it with their own license that required annual payments to their company. However that fork now appears to be dead. So there is no need to reinforce the copyright notice in every single file.
93 lines
2.7 KiB
Zig
93 lines
2.7 KiB
Zig
// Ported from musl, which is licensed under the MIT license:
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// https://git.musl-libc.org/cgit/musl/tree/COPYRIGHT
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//
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// https://git.musl-libc.org/cgit/musl/tree/src/math/copysignf.c
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// https://git.musl-libc.org/cgit/musl/tree/src/math/copysign.c
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const std = @import("../std.zig");
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const math = std.math;
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const expect = std.testing.expect;
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const maxInt = std.math.maxInt;
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/// Returns a value with the magnitude of x and the sign of y.
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pub fn copysign(comptime T: type, x: T, y: T) T {
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return switch (T) {
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f16 => copysign16(x, y),
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f32 => copysign32(x, y),
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f64 => copysign64(x, y),
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f128 => copysign128(x, y),
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else => @compileError("copysign not implemented for " ++ @typeName(T)),
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};
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}
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fn copysign16(x: f16, y: f16) f16 {
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const ux = @bitCast(u16, x);
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const uy = @bitCast(u16, y);
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const h1 = ux & (maxInt(u16) / 2);
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const h2 = uy & (@as(u16, 1) << 15);
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return @bitCast(f16, h1 | h2);
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}
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fn copysign32(x: f32, y: f32) f32 {
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const ux = @bitCast(u32, x);
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const uy = @bitCast(u32, y);
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const h1 = ux & (maxInt(u32) / 2);
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const h2 = uy & (@as(u32, 1) << 31);
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return @bitCast(f32, h1 | h2);
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}
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fn copysign64(x: f64, y: f64) f64 {
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const ux = @bitCast(u64, x);
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const uy = @bitCast(u64, y);
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const h1 = ux & (maxInt(u64) / 2);
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const h2 = uy & (@as(u64, 1) << 63);
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return @bitCast(f64, h1 | h2);
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}
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fn copysign128(x: f128, y: f128) f128 {
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const ux = @bitCast(u128, x);
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const uy = @bitCast(u128, y);
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const h1 = ux & (maxInt(u128) / 2);
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const h2 = uy & (@as(u128, 1) << 127);
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return @bitCast(f128, h1 | h2);
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}
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test "math.copysign" {
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try expect(copysign(f16, 1.0, 1.0) == copysign16(1.0, 1.0));
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try expect(copysign(f32, 1.0, 1.0) == copysign32(1.0, 1.0));
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try expect(copysign(f64, 1.0, 1.0) == copysign64(1.0, 1.0));
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try expect(copysign(f128, 1.0, 1.0) == copysign128(1.0, 1.0));
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}
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test "math.copysign16" {
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try expect(copysign16(5.0, 1.0) == 5.0);
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try expect(copysign16(5.0, -1.0) == -5.0);
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try expect(copysign16(-5.0, -1.0) == -5.0);
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try expect(copysign16(-5.0, 1.0) == 5.0);
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}
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test "math.copysign32" {
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try expect(copysign32(5.0, 1.0) == 5.0);
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try expect(copysign32(5.0, -1.0) == -5.0);
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try expect(copysign32(-5.0, -1.0) == -5.0);
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try expect(copysign32(-5.0, 1.0) == 5.0);
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}
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test "math.copysign64" {
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try expect(copysign64(5.0, 1.0) == 5.0);
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try expect(copysign64(5.0, -1.0) == -5.0);
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try expect(copysign64(-5.0, -1.0) == -5.0);
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try expect(copysign64(-5.0, 1.0) == 5.0);
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}
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test "math.copysign128" {
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try expect(copysign128(5.0, 1.0) == 5.0);
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try expect(copysign128(5.0, -1.0) == -5.0);
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try expect(copysign128(-5.0, -1.0) == -5.0);
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try expect(copysign128(-5.0, 1.0) == 5.0);
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}
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