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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.
39 lines
1.2 KiB
Zig
39 lines
1.2 KiB
Zig
const builtin = @import("builtin");
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const std = @import("std");
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const maxInt = std.math.maxInt;
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const implicitBit = @as(u64, 1) << 52;
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pub fn __floatunsidf(arg: u32) callconv(.C) f64 {
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@setRuntimeSafety(builtin.is_test);
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if (arg == 0) return 0.0;
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// The exponent is the width of abs(a)
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const exp = @as(u64, 31) - @clz(u32, arg);
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// Shift a into the significand field and clear the implicit bit
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const shift = @intCast(u6, 52 - exp);
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const mant = @as(u64, arg) << shift ^ implicitBit;
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return @bitCast(f64, mant | (exp + 1023) << 52);
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}
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pub fn __aeabi_ui2d(arg: u32) callconv(.AAPCS) f64 {
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@setRuntimeSafety(false);
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return @call(.{ .modifier = .always_inline }, __floatunsidf, .{arg});
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}
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fn test_one_floatunsidf(a: u32, expected: u64) !void {
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const r = __floatunsidf(a);
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try std.testing.expect(@bitCast(u64, r) == expected);
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}
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test "floatsidf" {
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// Test the produced bit pattern
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try test_one_floatunsidf(0, 0x0000000000000000);
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try test_one_floatunsidf(1, 0x3ff0000000000000);
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try test_one_floatunsidf(0x7FFFFFFF, 0x41dfffffffc00000);
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try test_one_floatunsidf(@intCast(u32, 0x80000000), 0x41e0000000000000);
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try test_one_floatunsidf(@intCast(u32, 0xFFFFFFFF), 0x41efffffffe00000);
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}
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