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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 | |
21 | namespace LIBC_NAMESPACE_DECL { |
22 | namespace fputil { |
23 | |
24 | template <bool IsDown> |
25 | LIBC_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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