| 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/properties/architectures.h" |
| 15 | |
| 16 | #if !defined(LIBC_TARGET_ARCH_IS_X86) |
| 17 | #error "Invalid include" |
| 18 | #endif |
| 19 | |
| 20 | namespace LIBC_NAMESPACE::fputil { |
| 21 | |
| 22 | template <bool IsDown> |
| 23 | LIBC_INLINE constexpr long double nextupdown(long double x) { |
| 24 | constexpr Sign sign = IsDown ? Sign::NEG : Sign::POS; |
| 25 | |
| 26 | using FPBits_t = FPBits<long double>; |
| 27 | FPBits_t xbits(x); |
| 28 | if (xbits.is_nan() || xbits == FPBits_t::max_normal(sign) || |
| 29 | xbits == FPBits_t::inf(sign)) |
| 30 | return x; |
| 31 | |
| 32 | if (x == 0.0l) |
| 33 | return FPBits_t::min_subnormal(sign).get_val(); |
| 34 | |
| 35 | using StorageType = typename FPBits_t::StorageType; |
| 36 | |
| 37 | if (xbits.sign() == sign) { |
| 38 | if (xbits.get_mantissa() == FPBits_t::FRACTION_MASK) { |
| 39 | xbits.set_mantissa(0); |
| 40 | xbits.set_biased_exponent(xbits.get_biased_exponent() + 1); |
| 41 | } else { |
| 42 | xbits = FPBits_t(StorageType(xbits.uintval() + 1)); |
| 43 | } |
| 44 | |
| 45 | return xbits.get_val(); |
| 46 | } |
| 47 | |
| 48 | if (xbits.get_mantissa() == 0) { |
| 49 | xbits.set_mantissa(FPBits_t::FRACTION_MASK); |
| 50 | xbits.set_biased_exponent(xbits.get_biased_exponent() - 1); |
| 51 | } else { |
| 52 | xbits = FPBits_t(StorageType(xbits.uintval() - 1)); |
| 53 | } |
| 54 | |
| 55 | return xbits.get_val(); |
| 56 | } |
| 57 | |
| 58 | } // namespace LIBC_NAMESPACE::fputil |
| 59 | |
| 60 | #endif // LLVM_LIBC_SRC___SUPPORT_FPUTIL_X86_64_NEXTUPDOWNLONGDOUBLE_H |
| 61 |