disas/libvixl/utils.h

   1 // Copyright 2013, 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 <math.h>
  31 #include <string.h>
  32 #include "globals.h"
  33
  34 namespace vixl {
  35
  36 // Macros for compile-time format checking.
  37 #if defined(__GNUC__)
  38 #define PRINTF_CHECK(format_index, varargs_index) \
  39   __attribute__((format(printf, format_index, varargs_index)))
  40 #else
  41 #define PRINTF_CHECK(format_index, varargs_index)
  42 #endif
  43
  44 // Check number width.
  45 inline bool is_intn(unsigned n, int64_t x) {
  46   VIXL_ASSERT((0 < n) && (n < 64));
  47   int64_t limit = INT64_C(1) << (n - 1);
  48   return (-limit <= x) && (x < limit);
  49 }
  50
  51 inline bool is_uintn(unsigned n, int64_t x) {
  52   VIXL_ASSERT((0 < n) && (n < 64));
  53   return !(x >> n);
  54 }
  55
  56 inline unsigned truncate_to_intn(unsigned n, int64_t x) {
  57   VIXL_ASSERT((0 < n) && (n < 64));
  58   return (x & ((INT64_C(1) << n) - 1));
  59 }
  60
  61 #define INT_1_TO_63_LIST(V)                                                    \
  62 V(1)  V(2)  V(3)  V(4)  V(5)  V(6)  V(7)  V(8)                                 \
  63 V(9)  V(10) V(11) V(12) V(13) V(14) V(15) V(16)                                \
  64 V(17) V(18) V(19) V(20) V(21) V(22) V(23) V(24)                                \
  65 V(25) V(26) V(27) V(28) V(29) V(30) V(31) V(32)                                \
  66 V(33) V(34) V(35) V(36) V(37) V(38) V(39) V(40)                                \
  67 V(41) V(42) V(43) V(44) V(45) V(46) V(47) V(48)                                \
  68 V(49) V(50) V(51) V(52) V(53) V(54) V(55) V(56)                                \
  69 V(57) V(58) V(59) V(60) V(61) V(62) V(63)
  70
  71 #define DECLARE_IS_INT_N(N)                                                    \
  72 inline bool is_int##N(int64_t x) { return is_intn(N, x); }
  73 #define DECLARE_IS_UINT_N(N)                                                   \
  74 inline bool is_uint##N(int64_t x) { return is_uintn(N, x); }
  75 #define DECLARE_TRUNCATE_TO_INT_N(N)                                           \
  76 inline int truncate_to_int##N(int x) { return truncate_to_intn(N, x); }
  77 INT_1_TO_63_LIST(DECLARE_IS_INT_N)
  78 INT_1_TO_63_LIST(DECLARE_IS_UINT_N)
  79 INT_1_TO_63_LIST(DECLARE_TRUNCATE_TO_INT_N)
  80 #undef DECLARE_IS_INT_N
  81 #undef DECLARE_IS_UINT_N
  82 #undef DECLARE_TRUNCATE_TO_INT_N
  83
  84 // Bit field extraction.
  85 inline uint32_t unsigned_bitextract_32(int msb, int lsb, uint32_t x) {
  86   return (x >> lsb) & ((1 << (1 + msb - lsb)) - 1);
  87 }
  88
  89 inline uint64_t unsigned_bitextract_64(int msb, int lsb, uint64_t x) {
  90   return (x >> lsb) & ((static_cast<uint64_t>(1) << (1 + msb - lsb)) - 1);
  91 }
  92
  93 inline int32_t signed_bitextract_32(int msb, int lsb, int32_t x) {
  94   return (x << (31 - msb)) >> (lsb + 31 - msb);
  95 }
  96
  97 inline int64_t signed_bitextract_64(int msb, int lsb, int64_t x) {
  98   return (x << (63 - msb)) >> (lsb + 63 - msb);
  99 }
 100
 101 // Floating point representation.
 102 uint32_t float_to_rawbits(float value);
 103 uint64_t double_to_rawbits(double value);
 104 float rawbits_to_float(uint32_t bits);
 105 double rawbits_to_double(uint64_t bits);
 106
 107
 108 // NaN tests.
 109 inline bool IsSignallingNaN(double num) {
 110   const uint64_t kFP64QuietNaNMask = UINT64_C(0x0008000000000000);
 111   uint64_t raw = double_to_rawbits(num);
 112   if (isnan(num) && ((raw & kFP64QuietNaNMask) == 0)) {
 113     return true;
 114   }
 115   return false;
 116 }
 117
 118
 119 inline bool IsSignallingNaN(float num) {
 120   const uint32_t kFP32QuietNaNMask = 0x00400000;
 121   uint32_t raw = float_to_rawbits(num);
 122   if (isnan(num) && ((raw & kFP32QuietNaNMask) == 0)) {
 123     return true;
 124   }
 125   return false;
 126 }
 127
 128
 129 template <typename T>
 130 inline bool IsQuietNaN(T num) {
 131   return isnan(num) && !IsSignallingNaN(num);
 132 }
 133
 134
 135 // Convert the NaN in 'num' to a quiet NaN.
 136 inline double ToQuietNaN(double num) {
 137   const uint64_t kFP64QuietNaNMask = UINT64_C(0x0008000000000000);
 138   VIXL_ASSERT(isnan(num));
 139   return rawbits_to_double(double_to_rawbits(num) | kFP64QuietNaNMask);
 140 }
 141
 142
 143 inline float ToQuietNaN(float num) {
 144   const uint32_t kFP32QuietNaNMask = 0x00400000;
 145   VIXL_ASSERT(isnan(num));
 146   return rawbits_to_float(float_to_rawbits(num) | kFP32QuietNaNMask);
 147 }
 148
 149
 150 // Fused multiply-add.
 151 inline double FusedMultiplyAdd(double op1, double op2, double a) {
 152   return fma(op1, op2, a);
 153 }
 154
 155
 156 inline float FusedMultiplyAdd(float op1, float op2, float a) {
 157   return fmaf(op1, op2, a);
 158 }
 159
 160
 161 // Bit counting.
 162 int CountLeadingZeros(uint64_t value, int width);
 163 int CountLeadingSignBits(int64_t value, int width);
 164 int CountTrailingZeros(uint64_t value, int width);
 165 int CountSetBits(uint64_t value, int width);
 166 uint64_t LowestSetBit(uint64_t value);
 167 bool IsPowerOf2(int64_t value);
 168
 169 // Pointer alignment
 170 // TODO: rename/refactor to make it specific to instructions.
 171 template<typename T>
 172 bool IsWordAligned(T pointer) {
 173   VIXL_ASSERT(sizeof(pointer) == sizeof(intptr_t));   // NOLINT(runtime/sizeof)
 174   return ((intptr_t)(pointer) & 3) == 0;
 175 }
 176
 177 // Increment a pointer until it has the specified alignment.
 178 template<class T>
 179 T AlignUp(T pointer, size_t alignment) {
 180   // Use C-style casts to get static_cast behaviour for integral types (T), and
 181   // reinterpret_cast behaviour for other types.
 182
 183   uintptr_t pointer_raw = (uintptr_t)pointer;
 184   VIXL_STATIC_ASSERT(sizeof(pointer) == sizeof(pointer_raw));
 185
 186   size_t align_step = (alignment - pointer_raw) % alignment;
 187   VIXL_ASSERT((pointer_raw + align_step) % alignment == 0);
 188
 189   return (T)(pointer_raw + align_step);
 190 }
 191
 192 // Decrement a pointer until it has the specified alignment.
 193 template<class T>
 194 T AlignDown(T pointer, size_t alignment) {
 195   // Use C-style casts to get static_cast behaviour for integral types (T), and
 196   // reinterpret_cast behaviour for other types.
 197
 198   uintptr_t pointer_raw = (uintptr_t)pointer;
 199   VIXL_STATIC_ASSERT(sizeof(pointer) == sizeof(pointer_raw));
 200
 201   size_t align_step = pointer_raw % alignment;
 202   VIXL_ASSERT((pointer_raw - align_step) % alignment == 0);
 203
 204   return (T)(pointer_raw - align_step);
 205 }
 206
 207 }  // namespace vixl
 208
 209 #endif  // VIXL_UTILS_H