1 // Copyright 2017 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include <cstdint> 6 7 namespace v8 { 8 namespace internal { 9 10 // ISA constants. -------------------------------------------------------------- 11 12 // The following code initializes float/double variables with bit patterns 13 // without using static initializers (which is surprisingly difficult in 14 // C++). These variables are used by client code as extern float16, 15 // extern float and extern double types, which works because (I think) the 16 // linker ignores the types. This is kept in a separate source file to 17 // avoid breaking jumbo builds. 18 // 19 // TODO(mostynb): replace these with std::numeric_limits constexpr's where 20 // possible, and figure out how to replace *DefaultNaN with something clean, 21 // then move this code back into instructions-arm64.cc with the same types 22 // that client code uses. 23 24 extern const uint16_t kFP16PositiveInfinity = 0x7C00; 25 extern const uint16_t kFP16NegativeInfinity = 0xFC00; 26 extern const uint32_t kFP32PositiveInfinity = 0x7F800000; 27 extern const uint32_t kFP32NegativeInfinity = 0xFF800000; 28 extern const uint64_t kFP64PositiveInfinity = 0x7FF0000000000000UL; 29 extern const uint64_t kFP64NegativeInfinity = 0xFFF0000000000000UL; 30 31 // This value is a signalling NaN as both a double and as a float (taking the 32 // least-significant word). 33 extern const uint64_t kFP64SignallingNaN = 0x7FF000007F800001; 34 extern const uint32_t kFP32SignallingNaN = 0x7F800001; 35 36 // A similar value, but as a quiet NaN. 37 extern const uint64_t kFP64QuietNaN = 0x7FF800007FC00001; 38 extern const uint32_t kFP32QuietNaN = 0x7FC00001; 39 40 // The default NaN values (for FPCR.DN=1). 41 extern const uint64_t kFP64DefaultNaN = 0x7FF8000000000000UL; 42 extern const uint32_t kFP32DefaultNaN = 0x7FC00000; 43 extern const uint16_t kFP16DefaultNaN = 0x7E00; 44 45 } // namespace internal 46 } // namespace v8 47
