Meg's Mirrors

zig

1	const std = @import("std");
2	const builtin = @import("builtin");
3	const math = std.math;
4	const arch = builtin.cpu.arch;
5	const compiler_rt = @import("../compiler_rt.zig");
6	const symbol = compiler_rt.symbol;
7
8	comptime {
9	symbol(&__fmaxh, "__fmaxh");
10	symbol(&fmaxf, "fmaxf");
11	symbol(&fmax, "fmax");
12	symbol(&__fmaxx, "__fmaxx");
13	symbol(&fmaxq, "fmaxf128");
14	symbol(&fmaxl, "fmaxl");
15	}
16
17	fn __fmaxh(x: compiler_rt.f16.Abi, y: compiler_rt.f16.Abi) callconv(.c) compiler_rt.f16.Abi {
18	return compiler_rt.f16.toAbi(fmax_f16(compiler_rt.f16.fromAbi(x), compiler_rt.f16.fromAbi(y)));
19	}
20	pub fn fmax_f16(x: f16, y: f16) f16 {
21	return generic_fmax(f16, x, y);
22	}
23
24	fn fmaxf(x: compiler_rt.f32.Abi, y: compiler_rt.f32.Abi) callconv(.c) compiler_rt.f32.Abi {
25	return compiler_rt.f32.toAbi(fmax_f32(compiler_rt.f32.fromAbi(x), compiler_rt.f32.fromAbi(y)));
26	}
27	pub fn fmax_f32(x: f32, y: f32) f32 {
28	return generic_fmax(f32, x, y);
29	}
30
31	fn fmax(x: compiler_rt.f64.Abi, y: compiler_rt.f64.Abi) callconv(.c) compiler_rt.f64.Abi {
32	return compiler_rt.f64.toAbi(fmax_f64(compiler_rt.f64.fromAbi(x), compiler_rt.f64.fromAbi(y)));
33	}
34	pub fn fmax_f64(x: f64, y: f64) f64 {
35	return generic_fmax(f64, x, y);
36	}
37
38	fn __fmaxx(x: compiler_rt.f80.Abi, y: compiler_rt.f80.Abi) callconv(.c) compiler_rt.f80.Abi {
39	return compiler_rt.f80.toAbi(fmax_f80(compiler_rt.f80.fromAbi(x), compiler_rt.f80.fromAbi(y)));
40	}
41	pub fn fmax_f80(x: f80, y: f80) f80 {
42	return generic_fmax(f80, x, y);
43	}
44
45	fn fmaxq(x: compiler_rt.f128.Abi, y: compiler_rt.f128.Abi) callconv(.c) compiler_rt.f128.Abi {
46	return compiler_rt.f128.toAbi(fmax_f128(compiler_rt.f128.fromAbi(x), compiler_rt.f128.fromAbi(y)));
47	}
48	pub fn fmax_f128(x: f128, y: f128) f128 {
49	return generic_fmax(f128, x, y);
50	}
51
52	pub fn fmaxl(x: c_longdouble, y: c_longdouble) callconv(.c) c_longdouble {
53	switch (@typeInfo(c_longdouble).float.bits) {
54	64 => return fmax_f64(x, y),
55	80 => return fmax_f80(x, y),
56	128 => return fmax_f128(x, y),
57	else => comptime unreachable,
58	}
59	}
60
61	inline fn generic_fmax(comptime T: type, x: T, y: T) T {
62	if (math.isNan(x))
63	return y;
64	if (math.isNan(y))
65	return x;
66	if (math.signbit(x) != math.signbit(y))
67	return if (math.signbit(x)) y else x;
68	return if (x < y) y else x;
69	}
70
71	test "generic_fmax" {
72	inline for ([_]type{ f32, f64, c_longdouble, f80, f128 }) |T| {
73	const nan_val = math.nan(T);
74	const Int = @Int(.unsigned, @bitSizeOf(T));
75
76	try std.testing.expect(math.isNan(generic_fmax(T, nan_val, nan_val)));
77	try std.testing.expectEqual(@as(T, 1.0), generic_fmax(T, nan_val, 1.0));
78	try std.testing.expectEqual(@as(T, 1.0), generic_fmax(T, 1.0, nan_val));
79
80	try std.testing.expectEqual(@as(T, 10.0), generic_fmax(T, 1.0, 10.0));
81	try std.testing.expectEqual(@as(T, 1.0), generic_fmax(T, 1.0, -1.0));
82
83	try std.testing.expectEqual(@as(Int, @bitCast(@as(T, 0.0))), @as(Int, @bitCast(generic_fmax(T, 0.0, -0.0))));
84	try std.testing.expectEqual(@as(Int, @bitCast(@as(T, 0.0))), @as(Int, @bitCast(generic_fmax(T, -0.0, 0.0))));
85	}
86	}