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> nextupdown(long double x)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