| // Copyright 2013 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef V8_ARM64_UTILS_ARM64_H_ |
| #define V8_ARM64_UTILS_ARM64_H_ |
| |
| #include <cmath> |
| |
| #include "src/arm64/constants-arm64.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| // These are global assumptions in v8. |
| STATIC_ASSERT((static_cast<int32_t>(-1) >> 1) == -1); |
| STATIC_ASSERT((static_cast<uint32_t>(-1) >> 1) == 0x7FFFFFFF); |
| |
| // Floating point representation. |
| static inline uint32_t float_to_rawbits(float value) { |
| uint32_t bits = 0; |
| memcpy(&bits, &value, 4); |
| return bits; |
| } |
| |
| |
| static inline uint64_t double_to_rawbits(double value) { |
| uint64_t bits = 0; |
| memcpy(&bits, &value, 8); |
| return bits; |
| } |
| |
| |
| static inline float rawbits_to_float(uint32_t bits) { |
| float value = 0.0; |
| memcpy(&value, &bits, 4); |
| return value; |
| } |
| |
| |
| static inline double rawbits_to_double(uint64_t bits) { |
| double value = 0.0; |
| memcpy(&value, &bits, 8); |
| return value; |
| } |
| |
| |
| // Bit counting. |
| int CountLeadingZeros(uint64_t value, int width); |
| int CountLeadingSignBits(int64_t value, int width); |
| int CountTrailingZeros(uint64_t value, int width); |
| int CountSetBits(uint64_t value, int width); |
| uint64_t LargestPowerOf2Divisor(uint64_t value); |
| int MaskToBit(uint64_t mask); |
| |
| |
| template <typename T> |
| T ReverseBytes(T value, int block_bytes_log2) { |
| DCHECK((sizeof(value) == 4) || (sizeof(value) == 8)); |
| DCHECK((1U << block_bytes_log2) <= sizeof(value)); |
| // Split the 64-bit value into an 8-bit array, where b[0] is the least |
| // significant byte, and b[7] is the most significant. |
| uint8_t bytes[8]; |
| uint64_t mask = 0xff00000000000000; |
| for (int i = 7; i >= 0; i--) { |
| bytes[i] = (static_cast<uint64_t>(value) & mask) >> (i * 8); |
| mask >>= 8; |
| } |
| |
| // Permutation tables for REV instructions. |
| // permute_table[0] is used by REV16_x, REV16_w |
| // permute_table[1] is used by REV32_x, REV_w |
| // permute_table[2] is used by REV_x |
| DCHECK((0 < block_bytes_log2) && (block_bytes_log2 < 4)); |
| static const uint8_t permute_table[3][8] = {{6, 7, 4, 5, 2, 3, 0, 1}, |
| {4, 5, 6, 7, 0, 1, 2, 3}, |
| {0, 1, 2, 3, 4, 5, 6, 7}}; |
| T result = 0; |
| for (int i = 0; i < 8; i++) { |
| result <<= 8; |
| result |= bytes[permute_table[block_bytes_log2 - 1][i]]; |
| } |
| return result; |
| } |
| |
| |
| // NaN tests. |
| inline bool IsSignallingNaN(double num) { |
| uint64_t raw = double_to_rawbits(num); |
| if (std::isnan(num) && ((raw & kDQuietNanMask) == 0)) { |
| return true; |
| } |
| return false; |
| } |
| |
| |
| inline bool IsSignallingNaN(float num) { |
| uint32_t raw = float_to_rawbits(num); |
| if (std::isnan(num) && ((raw & kSQuietNanMask) == 0)) { |
| return true; |
| } |
| return false; |
| } |
| |
| |
| template <typename T> |
| inline bool IsQuietNaN(T num) { |
| return std::isnan(num) && !IsSignallingNaN(num); |
| } |
| |
| |
| // Convert the NaN in 'num' to a quiet NaN. |
| inline double ToQuietNaN(double num) { |
| DCHECK(std::isnan(num)); |
| return rawbits_to_double(double_to_rawbits(num) | kDQuietNanMask); |
| } |
| |
| |
| inline float ToQuietNaN(float num) { |
| DCHECK(std::isnan(num)); |
| return rawbits_to_float(float_to_rawbits(num) | kSQuietNanMask); |
| } |
| |
| |
| // Fused multiply-add. |
| inline double FusedMultiplyAdd(double op1, double op2, double a) { |
| return fma(op1, op2, a); |
| } |
| |
| |
| inline float FusedMultiplyAdd(float op1, float op2, float a) { |
| return fmaf(op1, op2, a); |
| } |
| |
| } // namespace internal |
| } // namespace v8 |
| |
| #endif // V8_ARM64_UTILS_ARM64_H_ |