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 defined(__GNUC__)
39 #define PRINTF_CHECK(format_index, varargs_index) \
40 __attribute__((format(printf, format_index, varargs_index)))
41 #else
42 #define PRINTF_CHECK(format_index, varargs_index)
43 #endif
44
45 // Check number width.
is_intn(unsigned n,int64_t x)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
is_uintn(unsigned n,int64_t x)52 inline bool is_uintn(unsigned n, int64_t x) {
53 VIXL_ASSERT((0 < n) && (n < 64));
54 return !(x >> n);
55 }
56
truncate_to_intn(unsigned n,int64_t x)57 inline unsigned truncate_to_intn(unsigned n, int64_t x) {
58 VIXL_ASSERT((0 < n) && (n < 64));
59 return (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 int truncate_to_int##N(int x) { return truncate_to_intn(N, x); }
78 INT_1_TO_63_LIST(DECLARE_IS_INT_N)
INT_1_TO_63_LIST(DECLARE_IS_UINT_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
unsigned_bitextract_64(int msb,int lsb,uint64_t x)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
signed_bitextract_32(int msb,int lsb,int32_t x)94 inline int32_t signed_bitextract_32(int msb, int lsb, int32_t x) {
95 return (x << (31 - msb)) >> (lsb + 31 - msb);
96 }
97
signed_bitextract_64(int msb,int lsb,int64_t x)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.
IsSignallingNaN(double num)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
IsSignallingNaN(float num)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
IsSignallingNaN(float16 num)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>
IsQuietNaN(T num)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.
ToQuietNaN(double num)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
ToQuietNaN(float num)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.
FusedMultiplyAdd(double op1,double op2,double a)171 inline double FusedMultiplyAdd(double op1, double op2, double a) {
172 return fma(op1, op2, a);
173 }
174
175
FusedMultiplyAdd(float op1,float op2,float a)176 inline float FusedMultiplyAdd(float op1, float op2, float a) {
177 return fmaf(op1, op2, a);
178 }
179
180
LowestSetBit(uint64_t value)181 inline uint64_t LowestSetBit(uint64_t value) {
182 return value & -value;
183 }
184
185
186 template<typename T>
HighestSetBitPosition(T value)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>
WhichPowerOf2(V value)194 inline int WhichPowerOf2(V value) {
195 VIXL_ASSERT(IsPowerOf2(value));
196 return CountTrailingZeros(value);
197 }
198
199 unsigned CountClearHalfWords(uint64_t imm, unsigned reg_size);
200
201 // Pointer alignment
202 // TODO: rename/refactor to make it specific to instructions.
203 template<typename T>
IsWordAligned(T pointer)204 bool IsWordAligned(T pointer) {
205 VIXL_ASSERT(sizeof(pointer) == sizeof(intptr_t)); // NOLINT(runtime/sizeof)
206 return ((intptr_t)(pointer) & 3) == 0;
207 }
208
209 // Increment a pointer (up to 64 bits) until it has the specified alignment.
210 template<class T>
AlignUp(T pointer,size_t alignment)211 T AlignUp(T pointer, size_t alignment) {
212 // Use C-style casts to get static_cast behaviour for integral types (T), and
213 // reinterpret_cast behaviour for other types.
214
215 uint64_t pointer_raw = (uint64_t)pointer;
216 VIXL_STATIC_ASSERT(sizeof(pointer) <= sizeof(pointer_raw));
217
218 size_t align_step = (alignment - pointer_raw) % alignment;
219 VIXL_ASSERT((pointer_raw + align_step) % alignment == 0);
220
221 return (T)(pointer_raw + align_step);
222 }
223
224 // Decrement a pointer (up to 64 bits) until it has the specified alignment.
225 template<class T>
AlignDown(T pointer,size_t alignment)226 T AlignDown(T pointer, size_t alignment) {
227 // Use C-style casts to get static_cast behaviour for integral types (T), and
228 // reinterpret_cast behaviour for other types.
229
230 uint64_t pointer_raw = (uint64_t)pointer;
231 VIXL_STATIC_ASSERT(sizeof(pointer) <= sizeof(pointer_raw));
232
233 size_t align_step = pointer_raw % alignment;
234 VIXL_ASSERT((pointer_raw - align_step) % alignment == 0);
235
236 return (T)(pointer_raw - align_step);
237 }
238
239 } // namespace vixl
240
241 #endif // VIXL_UTILS_H
242