Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1 | // Copyright 2013 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 | #ifndef V8_ARM64_UTILS_ARM64_H_ |
| 6 | #define V8_ARM64_UTILS_ARM64_H_ |
| 7 | |
| 8 | #include <cmath> |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 9 | |
| 10 | #include "src/arm64/constants-arm64.h" |
| 11 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 12 | namespace v8 { |
| 13 | namespace internal { |
| 14 | |
| 15 | // These are global assumptions in v8. |
| 16 | STATIC_ASSERT((static_cast<int32_t>(-1) >> 1) == -1); |
| 17 | STATIC_ASSERT((static_cast<uint32_t>(-1) >> 1) == 0x7FFFFFFF); |
| 18 | |
| 19 | // Floating point representation. |
| 20 | static inline uint32_t float_to_rawbits(float value) { |
| 21 | uint32_t bits = 0; |
| 22 | memcpy(&bits, &value, 4); |
| 23 | return bits; |
| 24 | } |
| 25 | |
| 26 | |
| 27 | static inline uint64_t double_to_rawbits(double value) { |
| 28 | uint64_t bits = 0; |
| 29 | memcpy(&bits, &value, 8); |
| 30 | return bits; |
| 31 | } |
| 32 | |
| 33 | |
| 34 | static inline float rawbits_to_float(uint32_t bits) { |
| 35 | float value = 0.0; |
| 36 | memcpy(&value, &bits, 4); |
| 37 | return value; |
| 38 | } |
| 39 | |
| 40 | |
| 41 | static inline double rawbits_to_double(uint64_t bits) { |
| 42 | double value = 0.0; |
| 43 | memcpy(&value, &bits, 8); |
| 44 | return value; |
| 45 | } |
| 46 | |
| 47 | |
| 48 | // Bit counting. |
| 49 | int CountLeadingZeros(uint64_t value, int width); |
| 50 | int CountLeadingSignBits(int64_t value, int width); |
| 51 | int CountTrailingZeros(uint64_t value, int width); |
| 52 | int CountSetBits(uint64_t value, int width); |
| 53 | uint64_t LargestPowerOf2Divisor(uint64_t value); |
| 54 | int MaskToBit(uint64_t mask); |
| 55 | |
| 56 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 57 | template <typename T> |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 58 | T ReverseBytes(T value, int block_bytes_log2) { |
| 59 | DCHECK((sizeof(value) == 4) || (sizeof(value) == 8)); |
| 60 | DCHECK((1U << block_bytes_log2) <= sizeof(value)); |
| 61 | // Split the 64-bit value into an 8-bit array, where b[0] is the least |
| 62 | // significant byte, and b[7] is the most significant. |
| 63 | uint8_t bytes[8]; |
| 64 | uint64_t mask = 0xff00000000000000; |
| 65 | for (int i = 7; i >= 0; i--) { |
| 66 | bytes[i] = (static_cast<uint64_t>(value) & mask) >> (i * 8); |
| 67 | mask >>= 8; |
| 68 | } |
| 69 | |
| 70 | // Permutation tables for REV instructions. |
| 71 | // permute_table[0] is used by REV16_x, REV16_w |
| 72 | // permute_table[1] is used by REV32_x, REV_w |
| 73 | // permute_table[2] is used by REV_x |
| 74 | DCHECK((0 < block_bytes_log2) && (block_bytes_log2 < 4)); |
| 75 | static const uint8_t permute_table[3][8] = {{6, 7, 4, 5, 2, 3, 0, 1}, |
| 76 | {4, 5, 6, 7, 0, 1, 2, 3}, |
| 77 | {0, 1, 2, 3, 4, 5, 6, 7}}; |
| 78 | T result = 0; |
| 79 | for (int i = 0; i < 8; i++) { |
| 80 | result <<= 8; |
| 81 | result |= bytes[permute_table[block_bytes_log2 - 1][i]]; |
| 82 | } |
| 83 | return result; |
| 84 | } |
| 85 | |
| 86 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 87 | // NaN tests. |
| 88 | inline bool IsSignallingNaN(double num) { |
| 89 | uint64_t raw = double_to_rawbits(num); |
| 90 | if (std::isnan(num) && ((raw & kDQuietNanMask) == 0)) { |
| 91 | return true; |
| 92 | } |
| 93 | return false; |
| 94 | } |
| 95 | |
| 96 | |
| 97 | inline bool IsSignallingNaN(float num) { |
| 98 | uint32_t raw = float_to_rawbits(num); |
| 99 | if (std::isnan(num) && ((raw & kSQuietNanMask) == 0)) { |
| 100 | return true; |
| 101 | } |
| 102 | return false; |
| 103 | } |
| 104 | |
| 105 | |
| 106 | template <typename T> |
| 107 | inline bool IsQuietNaN(T num) { |
| 108 | return std::isnan(num) && !IsSignallingNaN(num); |
| 109 | } |
| 110 | |
| 111 | |
| 112 | // Convert the NaN in 'num' to a quiet NaN. |
| 113 | inline double ToQuietNaN(double num) { |
| 114 | DCHECK(std::isnan(num)); |
| 115 | return rawbits_to_double(double_to_rawbits(num) | kDQuietNanMask); |
| 116 | } |
| 117 | |
| 118 | |
| 119 | inline float ToQuietNaN(float num) { |
| 120 | DCHECK(std::isnan(num)); |
| 121 | return rawbits_to_float(float_to_rawbits(num) | kSQuietNanMask); |
| 122 | } |
| 123 | |
| 124 | |
| 125 | // Fused multiply-add. |
| 126 | inline double FusedMultiplyAdd(double op1, double op2, double a) { |
| 127 | return fma(op1, op2, a); |
| 128 | } |
| 129 | |
| 130 | |
| 131 | inline float FusedMultiplyAdd(float op1, float op2, float a) { |
| 132 | return fmaf(op1, op2, a); |
| 133 | } |
| 134 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 135 | } // namespace internal |
| 136 | } // namespace v8 |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 137 | |
| 138 | #endif // V8_ARM64_UTILS_ARM64_H_ |