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1//===-- nextupdown implementation for x86 long double numbers ---*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLVM_LIBC_SRC___SUPPORT_FPUTIL_X86_64_NEXTUPDOWNLONGDOUBLE_H
10#define LLVM_LIBC_SRC___SUPPORT_FPUTIL_X86_64_NEXTUPDOWNLONGDOUBLE_H
11
12#include "src/__support/FPUtil/FPBits.h"
13#include "src/__support/macros/attributes.h"
14#include "src/__support/macros/config.h"
15#include "src/__support/macros/properties/architectures.h"
16
17#if !defined(LIBC_TARGET_ARCH_IS_X86)
18#error "Invalid include"
19#endif
20
21namespace LIBC_NAMESPACE_DECL {
22namespace fputil {
23
24template <bool IsDown>
25LIBC_INLINE constexpr long double nextupdown(long double x) {
26 constexpr Sign sign = IsDown ? Sign::NEG : Sign::POS;
27
28 using FPBits_t = FPBits<long double>;
29 FPBits_t xbits(x);
30 if (xbits.is_nan() || xbits == FPBits_t::max_normal(sign) ||
31 xbits == FPBits_t::inf(sign))
32 return x;
33
34 if (x == 0.0l)
35 return FPBits_t::min_subnormal(sign).get_val();
36
37 using StorageType = typename FPBits_t::StorageType;
38
39 if (xbits.sign() == sign) {
40 if (xbits.get_mantissa() == FPBits_t::FRACTION_MASK) {
41 xbits.set_mantissa(0);
42 xbits.set_biased_exponent(xbits.get_biased_exponent() + 1);
43 } else {
44 xbits = FPBits_t(StorageType(xbits.uintval() + 1));
45 }
46
47 return xbits.get_val();
48 }
49
50 if (xbits.get_mantissa() == 0) {
51 xbits.set_mantissa(FPBits_t::FRACTION_MASK);
52 xbits.set_biased_exponent(xbits.get_biased_exponent() - 1);
53 } else {
54 xbits = FPBits_t(StorageType(xbits.uintval() - 1));
55 }
56
57 return xbits.get_val();
58}
59
60} // namespace fputil
61} // namespace LIBC_NAMESPACE_DECL
62
63#endif // LLVM_LIBC_SRC___SUPPORT_FPUTIL_X86_64_NEXTUPDOWNLONGDOUBLE_H
64

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source code of libc/src/__support/FPUtil/x86_64/NextUpDownLongDouble.h