disas/libvixl/vixl/utils.h

   1 // Copyright 2015, ARM Limited
   2 // All rights reserved.
   3 //
   4 // Redistribution and use in source and binary forms, with or without
   5 // modification, are permitted provided that the following conditions are met:
   6 //
   7 //   * Redistributions of source code must retain the above copyright notice,
   8 //     this list of conditions and the following disclaimer.
   9 //   * Redistributions in binary form must reproduce the above copyright notice,
  10 //     this list of conditions and the following disclaimer in the documentation
  11 //     and/or other materials provided with the distribution.
  12 //   * Neither the name of ARM Limited nor the names of its contributors may be
  13 //     used to endorse or promote products derived from this software without
  14 //     specific prior written permission.
  15 //
  16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
  17 // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  18 // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  19 // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
  20 // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21 // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  22 // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  23 // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  24 // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  25 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26
  27 #ifndef VIXL_UTILS_H
  28 #define VIXL_UTILS_H
  29
  30 #include <string.h>
  31 #include <cmath>
  32 #include "vixl/globals.h"
  33 #include "vixl/compiler-intrinsics.h"
  34
  35 namespace vixl {
  36
  37 // Macros for compile-time format checking.
  38 #if GCC_VERSION_OR_NEWER(4, 4, 0)
  39 #define PRINTF_CHECK(format_index, varargs_index) \
  40   __attribute__((format(gnu_printf, format_index, varargs_index)))
  41 #else
  42 #define PRINTF_CHECK(format_index, varargs_index)
  43 #endif
  44
  45 // Check number width.
  46 inline bool is_intn(unsigned n, int64_t x) {
  47   VIXL_ASSERT((0 < n) && (n < 64));
  48   int64_t limit = INT64_C(1) << (n - 1);
  49   return (-limit <= x) && (x < limit);
  50 }
  51
  52 inline bool is_uintn(unsigned n, int64_t x) {
  53   VIXL_ASSERT((0 < n) && (n < 64));
  54   return !(x >> n);
  55 }
  56
  57 inline uint32_t truncate_to_intn(unsigned n, int64_t x) {
  58   VIXL_ASSERT((0 < n) && (n < 64));
  59   return static_cast<uint32_t>(x & ((INT64_C(1) << n) - 1));
  60 }
  61
  62 #define INT_1_TO_63_LIST(V)                                                    \
  63 V(1)  V(2)  V(3)  V(4)  V(5)  V(6)  V(7)  V(8)                                 \
  64 V(9)  V(10) V(11) V(12) V(13) V(14) V(15) V(16)                                \
  65 V(17) V(18) V(19) V(20) V(21) V(22) V(23) V(24)                                \
  66 V(25) V(26) V(27) V(28) V(29) V(30) V(31) V(32)                                \
  67 V(33) V(34) V(35) V(36) V(37) V(38) V(39) V(40)                                \
  68 V(41) V(42) V(43) V(44) V(45) V(46) V(47) V(48)                                \
  69 V(49) V(50) V(51) V(52) V(53) V(54) V(55) V(56)                                \
  70 V(57) V(58) V(59) V(60) V(61) V(62) V(63)
  71
  72 #define DECLARE_IS_INT_N(N)                                                    \
  73 inline bool is_int##N(int64_t x) { return is_intn(N, x); }
  74 #define DECLARE_IS_UINT_N(N)                                                   \
  75 inline bool is_uint##N(int64_t x) { return is_uintn(N, x); }
  76 #define DECLARE_TRUNCATE_TO_INT_N(N)                                           \
  77 inline uint32_t truncate_to_int##N(int x) { return truncate_to_intn(N, x); }
  78 INT_1_TO_63_LIST(DECLARE_IS_INT_N)
  79 INT_1_TO_63_LIST(DECLARE_IS_UINT_N)
  80 INT_1_TO_63_LIST(DECLARE_TRUNCATE_TO_INT_N)
  81 #undef DECLARE_IS_INT_N
  82 #undef DECLARE_IS_UINT_N
  83 #undef DECLARE_TRUNCATE_TO_INT_N
  84
  85 // Bit field extraction.
  86 inline uint32_t unsigned_bitextract_32(int msb, int lsb, uint32_t x) {
  87   return (x >> lsb) & ((1 << (1 + msb - lsb)) - 1);
  88 }
  89
  90 inline uint64_t unsigned_bitextract_64(int msb, int lsb, uint64_t x) {
  91   return (x >> lsb) & ((static_cast<uint64_t>(1) << (1 + msb - lsb)) - 1);
  92 }
  93
  94 inline int32_t signed_bitextract_32(int msb, int lsb, int32_t x) {
  95   return (x << (31 - msb)) >> (lsb + 31 - msb);
  96 }
  97
  98 inline int64_t signed_bitextract_64(int msb, int lsb, int64_t x) {
  99   return (x << (63 - msb)) >> (lsb + 63 - msb);
 100 }
 101
 102 // Floating point representation.
 103 uint32_t float_to_rawbits(float value);
 104 uint64_t double_to_rawbits(double value);
 105 float rawbits_to_float(uint32_t bits);
 106 double rawbits_to_double(uint64_t bits);
 107
 108 uint32_t float_sign(float val);
 109 uint32_t float_exp(float val);
 110 uint32_t float_mantissa(float val);
 111 uint32_t double_sign(double val);
 112 uint32_t double_exp(double val);
 113 uint64_t double_mantissa(double val);
 114
 115 float float_pack(uint32_t sign, uint32_t exp, uint32_t mantissa);
 116 double double_pack(uint64_t sign, uint64_t exp, uint64_t mantissa);
 117
 118 // An fpclassify() function for 16-bit half-precision floats.
 119 int float16classify(float16 value);
 120
 121 // NaN tests.
 122 inline bool IsSignallingNaN(double num) {
 123   const uint64_t kFP64QuietNaNMask = UINT64_C(0x0008000000000000);
 124   uint64_t raw = double_to_rawbits(num);
 125   if (std::isnan(num) && ((raw & kFP64QuietNaNMask) == 0)) {
 126     return true;
 127   }
 128   return false;
 129 }
 130
 131
 132 inline bool IsSignallingNaN(float num) {
 133   const uint32_t kFP32QuietNaNMask = 0x00400000;
 134   uint32_t raw = float_to_rawbits(num);
 135   if (std::isnan(num) && ((raw & kFP32QuietNaNMask) == 0)) {
 136     return true;
 137   }
 138   return false;
 139 }
 140
 141
 142 inline bool IsSignallingNaN(float16 num) {
 143   const uint16_t kFP16QuietNaNMask = 0x0200;
 144   return (float16classify(num) == FP_NAN) &&
 145          ((num & kFP16QuietNaNMask) == 0);
 146 }
 147
 148
 149 template <typename T>
 150 inline bool IsQuietNaN(T num) {
 151   return std::isnan(num) && !IsSignallingNaN(num);
 152 }
 153
 154
 155 // Convert the NaN in 'num' to a quiet NaN.
 156 inline double ToQuietNaN(double num) {
 157   const uint64_t kFP64QuietNaNMask = UINT64_C(0x0008000000000000);
 158   VIXL_ASSERT(std::isnan(num));
 159   return rawbits_to_double(double_to_rawbits(num) | kFP64QuietNaNMask);
 160 }
 161
 162
 163 inline float ToQuietNaN(float num) {
 164   const uint32_t kFP32QuietNaNMask = 0x00400000;
 165   VIXL_ASSERT(std::isnan(num));
 166   return rawbits_to_float(float_to_rawbits(num) | kFP32QuietNaNMask);
 167 }
 168
 169
 170 // Fused multiply-add.
 171 inline double FusedMultiplyAdd(double op1, double op2, double a) {
 172   return fma(op1, op2, a);
 173 }
 174
 175
 176 inline float FusedMultiplyAdd(float op1, float op2, float a) {
 177   return fmaf(op1, op2, a);
 178 }
 179
 180
 181 inline uint64_t LowestSetBit(uint64_t value) {
 182   return value & -value;
 183 }
 184
 185
 186 template<typename T>
 187 inline int HighestSetBitPosition(T value) {
 188   VIXL_ASSERT(value != 0);
 189   return (sizeof(value) * 8 - 1) - CountLeadingZeros(value);
 190 }
 191
 192
 193 template<typename V>
 194 inline int WhichPowerOf2(V value) {
 195   VIXL_ASSERT(IsPowerOf2(value));
 196   return CountTrailingZeros(value);
 197 }
 198
 199
 200 unsigned CountClearHalfWords(uint64_t imm, unsigned reg_size);
 201
 202
 203 template <typename T>
 204 T ReverseBits(T value) {
 205   VIXL_ASSERT((sizeof(value) == 1) || (sizeof(value) == 2) ||
 206               (sizeof(value) == 4) || (sizeof(value) == 8));
 207   T result = 0;
 208   for (unsigned i = 0; i < (sizeof(value) * 8); i++) {
 209     result = (result << 1) | (value & 1);
 210     value >>= 1;
 211   }
 212   return result;
 213 }
 214
 215
 216 template <typename T>
 217 T ReverseBytes(T value, int block_bytes_log2) {
 218   VIXL_ASSERT((sizeof(value) == 4) || (sizeof(value) == 8));
 219   VIXL_ASSERT((1U << block_bytes_log2) <= sizeof(value));
 220   // Split the 64-bit value into an 8-bit array, where b[0] is the least
 221   // significant byte, and b[7] is the most significant.
 222   uint8_t bytes[8];
 223   uint64_t mask = UINT64_C(0xff00000000000000);
 224   for (int i = 7; i >= 0; i--) {
 225     bytes[i] = (static_cast<uint64_t>(value) & mask) >> (i * 8);
 226     mask >>= 8;
 227   }
 228
 229   // Permutation tables for REV instructions.
 230   //  permute_table[0] is used by REV16_x, REV16_w
 231   //  permute_table[1] is used by REV32_x, REV_w
 232   //  permute_table[2] is used by REV_x
 233   VIXL_ASSERT((0 < block_bytes_log2) && (block_bytes_log2 < 4));
 234   static const uint8_t permute_table[3][8] = { {6, 7, 4, 5, 2, 3, 0, 1},
 235                                                {4, 5, 6, 7, 0, 1, 2, 3},
 236                                                {0, 1, 2, 3, 4, 5, 6, 7} };
 237   T result = 0;
 238   for (int i = 0; i < 8; i++) {
 239     result <<= 8;
 240     result |= bytes[permute_table[block_bytes_log2 - 1][i]];
 241   }
 242   return result;
 243 }
 244
 245
 246 // Pointer alignment
 247 // TODO: rename/refactor to make it specific to instructions.
 248 template<typename T>
 249 bool IsWordAligned(T pointer) {
 250   VIXL_ASSERT(sizeof(pointer) == sizeof(intptr_t));   // NOLINT(runtime/sizeof)
 251   return ((intptr_t)(pointer) & 3) == 0;
 252 }
 253
 254 // Increment a pointer (up to 64 bits) until it has the specified alignment.
 255 template<class T>
 256 T AlignUp(T pointer, size_t alignment) {
 257   // Use C-style casts to get static_cast behaviour for integral types (T), and
 258   // reinterpret_cast behaviour for other types.
 259
 260   uint64_t pointer_raw = (uint64_t)pointer;
 261   VIXL_STATIC_ASSERT(sizeof(pointer) <= sizeof(pointer_raw));
 262
 263   size_t align_step = (alignment - pointer_raw) % alignment;
 264   VIXL_ASSERT((pointer_raw + align_step) % alignment == 0);
 265
 266   return (T)(pointer_raw + align_step);
 267 }
 268
 269 // Decrement a pointer (up to 64 bits) until it has the specified alignment.
 270 template<class T>
 271 T AlignDown(T pointer, size_t alignment) {
 272   // Use C-style casts to get static_cast behaviour for integral types (T), and
 273   // reinterpret_cast behaviour for other types.
 274
 275   uint64_t pointer_raw = (uint64_t)pointer;
 276   VIXL_STATIC_ASSERT(sizeof(pointer) <= sizeof(pointer_raw));
 277
 278   size_t align_step = pointer_raw % alignment;
 279   VIXL_ASSERT((pointer_raw - align_step) % alignment == 0);
 280
 281   return (T)(pointer_raw - align_step);
 282 }
 283
 284 }  // namespace vixl
 285
 286 #endif  // VIXL_UTILS_H