34 lines
1.0 KiB
Zig
34 lines
1.0 KiB
Zig
// SPDX-License-Identifier: MIT
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// Copyright (c) 2015-2020 Zig Contributors
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// This file is part of [zig](https://ziglang.org/), which is MIT licensed.
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// The MIT license requires this copyright notice to be included in all copies
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// and substantial portions of the software.
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const builtin = @import("builtin");
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const is_test = builtin.is_test;
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const std = @import("std");
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pub fn __floatunditf(a: u64) callconv(.C) f128 {
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@setRuntimeSafety(is_test);
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if (a == 0) {
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return 0;
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}
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const mantissa_bits = std.math.floatMantissaBits(f128);
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const exponent_bits = std.math.floatExponentBits(f128);
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const exponent_bias = (1 << (exponent_bits - 1)) - 1;
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const implicit_bit = 1 << mantissa_bits;
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const exp: u128 = (64 - 1) - @clz(u64, a);
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const shift: u7 = mantissa_bits - @intCast(u7, exp);
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var result: u128 = (@intCast(u128, a) << shift) ^ implicit_bit;
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result += (exp + exponent_bias) << mantissa_bits;
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return @bitCast(f128, result);
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}
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test "import floatunditf" {
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_ = @import("floatunditf_test.zig");
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}
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