1 /* Operations with long integers. 2 Copyright (C) 2006-2018 Free Software Foundation, Inc. 3 4 This file is part of GCC. 5 6 GCC is free software; you can redistribute it and/or modify it 7 under the terms of the GNU General Public License as published by the 8 Free Software Foundation; either version 3, or (at your option) any 9 later version. 10 11 GCC is distributed in the hope that it will be useful, but WITHOUT 12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GCC; see the file COPYING3. If not see 18 <http://www.gnu.org/licenses/>. */ 19 20 #ifndef DOUBLE_INT_H 21 #define DOUBLE_INT_H 22 23 /* A large integer is currently represented as a pair of HOST_WIDE_INTs. 24 It therefore represents a number with precision of 25 2 * HOST_BITS_PER_WIDE_INT bits (it is however possible that the 26 internal representation will change, if numbers with greater precision 27 are needed, so the users should not rely on it). The representation does 28 not contain any information about signedness of the represented value, so 29 it can be used to represent both signed and unsigned numbers. For 30 operations where the results depend on signedness (division, comparisons), 31 it must be specified separately. For each such operation, there are three 32 versions of the function -- double_int_op, that takes an extra UNS argument 33 giving the signedness of the values, and double_int_sop and double_int_uop 34 that stand for its specializations for signed and unsigned values. 35 36 You may also represent with numbers in smaller precision using double_int. 37 You however need to use double_int_ext (that fills in the bits of the 38 number over the prescribed precision with zeros or with the sign bit) before 39 operations that do not perform arithmetics modulo 2^precision (comparisons, 40 division), and possibly before storing the results, if you want to keep 41 them in some canonical form). In general, the signedness of double_int_ext 42 should match the signedness of the operation. 43 44 ??? The components of double_int differ in signedness mostly for 45 historical reasons (they replace an older structure used to represent 46 numbers with precision higher than HOST_WIDE_INT). It might be less 47 confusing to have them both signed or both unsigned. */ 48 49 struct double_int 50 { 51 /* Normally, we would define constructors to create instances. 52 Two things prevent us from doing so. 53 First, defining a constructor makes the class non-POD in C++03, 54 and we certainly want double_int to be a POD. 55 Second, the GCC conding conventions prefer explicit conversion, 56 and explicit conversion operators are not available until C++11. */ 57 58 static double_int from_uhwi (unsigned HOST_WIDE_INT cst); 59 static double_int from_shwi (HOST_WIDE_INT cst); 60 static double_int from_pair (HOST_WIDE_INT high, unsigned HOST_WIDE_INT low); 61 62 /* Construct from a fuffer of length LEN. BUFFER will be read according 63 to byte endianness and word endianness. */ 64 static double_int from_buffer (const unsigned char *buffer, int len); 65 66 /* No copy assignment operator or destructor to keep the type a POD. */ 67 68 /* There are some special value-creation static member functions. */ 69 70 static double_int mask (unsigned prec); 71 static double_int max_value (unsigned int prec, bool uns); 72 static double_int min_value (unsigned int prec, bool uns); 73 74 /* The following functions are mutating operations. */ 75 76 double_int &operator ++ (); // prefix 77 double_int &operator -- (); // prefix 78 double_int &operator *= (double_int); 79 double_int &operator += (double_int); 80 double_int &operator -= (double_int); 81 double_int &operator &= (double_int); 82 double_int &operator ^= (double_int); 83 double_int &operator |= (double_int); 84 85 /* The following functions are non-mutating operations. */ 86 87 /* Conversion functions. */ 88 89 HOST_WIDE_INT to_shwi () const; 90 unsigned HOST_WIDE_INT to_uhwi () const; 91 92 /* Conversion query functions. */ 93 94 bool fits_uhwi () const; 95 bool fits_shwi () const; 96 bool fits_hwi (bool uns) const; 97 98 /* Attribute query functions. */ 99 100 int trailing_zeros () const; 101 int popcount () const; 102 103 /* Arithmetic query operations. */ 104 105 bool multiple_of (double_int, bool, double_int *) const; 106 107 /* Arithmetic operation functions. */ 108 109 /* The following operations perform arithmetics modulo 2^precision, so you 110 do not need to call .ext between them, even if you are representing 111 numbers with precision less than HOST_BITS_PER_DOUBLE_INT bits. */ 112 113 double_int set_bit (unsigned) const; 114 double_int mul_with_sign (double_int, bool unsigned_p, bool *overflow) const; 115 double_int wide_mul_with_sign (double_int, bool unsigned_p, 116 double_int *higher, bool *overflow) const; 117 double_int add_with_sign (double_int, bool unsigned_p, bool *overflow) const; 118 double_int sub_with_overflow (double_int, bool *overflow) const; 119 double_int neg_with_overflow (bool *overflow) const; 120 121 double_int operator * (double_int) const; 122 double_int operator + (double_int) const; 123 double_int operator - (double_int) const; 124 double_int operator - () const; 125 double_int operator ~ () const; 126 double_int operator & (double_int) const; 127 double_int operator | (double_int) const; 128 double_int operator ^ (double_int) const; 129 double_int and_not (double_int) const; 130 131 double_int lshift (HOST_WIDE_INT count) const; 132 double_int lshift (HOST_WIDE_INT count, unsigned int prec, bool arith) const; 133 double_int rshift (HOST_WIDE_INT count) const; 134 double_int rshift (HOST_WIDE_INT count, unsigned int prec, bool arith) const; 135 double_int alshift (HOST_WIDE_INT count, unsigned int prec) const; 136 double_int arshift (HOST_WIDE_INT count, unsigned int prec) const; 137 double_int llshift (HOST_WIDE_INT count, unsigned int prec) const; 138 double_int lrshift (HOST_WIDE_INT count, unsigned int prec) const; 139 double_int lrotate (HOST_WIDE_INT count, unsigned int prec) const; 140 double_int rrotate (HOST_WIDE_INT count, unsigned int prec) const; 141 142 /* You must ensure that double_int::ext is called on the operands 143 of the following operations, if the precision of the numbers 144 is less than HOST_BITS_PER_DOUBLE_INT bits. */ 145 146 double_int div (double_int, bool, unsigned) const; 147 double_int sdiv (double_int, unsigned) const; 148 double_int udiv (double_int, unsigned) const; 149 double_int mod (double_int, bool, unsigned) const; 150 double_int smod (double_int, unsigned) const; 151 double_int umod (double_int, unsigned) const; 152 double_int divmod_with_overflow (double_int, bool, unsigned, 153 double_int *, bool *) const; 154 double_int divmod (double_int, bool, unsigned, double_int *) const; 155 double_int sdivmod (double_int, unsigned, double_int *) const; 156 double_int udivmod (double_int, unsigned, double_int *) const; 157 158 /* Precision control functions. */ 159 160 double_int ext (unsigned prec, bool uns) const; 161 double_int zext (unsigned prec) const; 162 double_int sext (unsigned prec) const; 163 164 /* Comparative functions. */ 165 166 bool is_zero () const; 167 bool is_one () const; 168 bool is_minus_one () const; 169 bool is_negative () const; 170 171 int cmp (double_int b, bool uns) const; 172 int ucmp (double_int b) const; 173 int scmp (double_int b) const; 174 175 bool ult (double_int b) const; 176 bool ule (double_int b) const; 177 bool ugt (double_int b) const; 178 bool slt (double_int b) const; 179 bool sle (double_int b) const; 180 bool sgt (double_int b) const; 181 182 double_int max (double_int b, bool uns); 183 double_int smax (double_int b); 184 double_int umax (double_int b); 185 186 double_int min (double_int b, bool uns); 187 double_int smin (double_int b); 188 double_int umin (double_int b); 189 190 bool operator == (double_int cst2) const; 191 bool operator != (double_int cst2) const; 192 193 /* Please migrate away from using these member variables publicly. */ 194 195 unsigned HOST_WIDE_INT low; 196 HOST_WIDE_INT high; 197 198 }; 199 200 #define HOST_BITS_PER_DOUBLE_INT (2 * HOST_BITS_PER_WIDE_INT) 201 202 /* Constructors and conversions. */ 203 204 /* Constructs double_int from integer CST. The bits over the precision of 205 HOST_WIDE_INT are filled with the sign bit. */ 206 207 inline double_int 208 double_int::from_shwi (HOST_WIDE_INT cst) 209 { 210 double_int r; 211 r.low = (unsigned HOST_WIDE_INT) cst; 212 r.high = cst < 0 ? -1 : 0; 213 return r; 214 } 215 216 /* Some useful constants. */ 217 /* FIXME(crowl): Maybe remove after converting callers? 218 The problem is that a named constant would not be as optimizable, 219 while the functional syntax is more verbose. */ 220 221 #define double_int_minus_one (double_int::from_shwi (-1)) 222 #define double_int_zero (double_int::from_shwi (0)) 223 #define double_int_one (double_int::from_shwi (1)) 224 #define double_int_two (double_int::from_shwi (2)) 225 #define double_int_ten (double_int::from_shwi (10)) 226 227 /* Constructs double_int from unsigned integer CST. The bits over the 228 precision of HOST_WIDE_INT are filled with zeros. */ 229 230 inline double_int 231 double_int::from_uhwi (unsigned HOST_WIDE_INT cst) 232 { 233 double_int r; 234 r.low = cst; 235 r.high = 0; 236 return r; 237 } 238 239 inline double_int 240 double_int::from_pair (HOST_WIDE_INT high, unsigned HOST_WIDE_INT low) 241 { 242 double_int r; 243 r.low = low; 244 r.high = high; 245 return r; 246 } 247 248 inline double_int & 249 double_int::operator ++ () 250 { 251 *this += double_int_one; 252 return *this; 253 } 254 255 inline double_int & 256 double_int::operator -- () 257 { 258 *this -= double_int_one; 259 return *this; 260 } 261 262 inline double_int & 263 double_int::operator &= (double_int b) 264 { 265 *this = *this & b; 266 return *this; 267 } 268 269 inline double_int & 270 double_int::operator ^= (double_int b) 271 { 272 *this = *this ^ b; 273 return *this; 274 } 275 276 inline double_int & 277 double_int::operator |= (double_int b) 278 { 279 *this = *this | b; 280 return *this; 281 } 282 283 /* Returns value of CST as a signed number. CST must satisfy 284 double_int::fits_signed. */ 285 286 inline HOST_WIDE_INT 287 double_int::to_shwi () const 288 { 289 return (HOST_WIDE_INT) low; 290 } 291 292 /* Returns value of CST as an unsigned number. CST must satisfy 293 double_int::fits_unsigned. */ 294 295 inline unsigned HOST_WIDE_INT 296 double_int::to_uhwi () const 297 { 298 return low; 299 } 300 301 /* Returns true if CST fits in unsigned HOST_WIDE_INT. */ 302 303 inline bool 304 double_int::fits_uhwi () const 305 { 306 return high == 0; 307 } 308 309 /* Logical operations. */ 310 311 /* Returns ~A. */ 312 313 inline double_int 314 double_int::operator ~ () const 315 { 316 double_int result; 317 result.low = ~low; 318 result.high = ~high; 319 return result; 320 } 321 322 /* Returns A | B. */ 323 324 inline double_int 325 double_int::operator | (double_int b) const 326 { 327 double_int result; 328 result.low = low | b.low; 329 result.high = high | b.high; 330 return result; 331 } 332 333 /* Returns A & B. */ 334 335 inline double_int 336 double_int::operator & (double_int b) const 337 { 338 double_int result; 339 result.low = low & b.low; 340 result.high = high & b.high; 341 return result; 342 } 343 344 /* Returns A & ~B. */ 345 346 inline double_int 347 double_int::and_not (double_int b) const 348 { 349 double_int result; 350 result.low = low & ~b.low; 351 result.high = high & ~b.high; 352 return result; 353 } 354 355 /* Returns A ^ B. */ 356 357 inline double_int 358 double_int::operator ^ (double_int b) const 359 { 360 double_int result; 361 result.low = low ^ b.low; 362 result.high = high ^ b.high; 363 return result; 364 } 365 366 void dump_double_int (FILE *, double_int, bool); 367 368 #define ALL_ONES HOST_WIDE_INT_M1U 369 370 /* The operands of the following comparison functions must be processed 371 with double_int_ext, if their precision is less than 372 HOST_BITS_PER_DOUBLE_INT bits. */ 373 374 /* Returns true if CST is zero. */ 375 376 inline bool 377 double_int::is_zero () const 378 { 379 return low == 0 && high == 0; 380 } 381 382 /* Returns true if CST is one. */ 383 384 inline bool 385 double_int::is_one () const 386 { 387 return low == 1 && high == 0; 388 } 389 390 /* Returns true if CST is minus one. */ 391 392 inline bool 393 double_int::is_minus_one () const 394 { 395 return low == ALL_ONES && high == -1; 396 } 397 398 /* Returns true if CST is negative. */ 399 400 inline bool 401 double_int::is_negative () const 402 { 403 return high < 0; 404 } 405 406 /* Returns true if CST1 == CST2. */ 407 408 inline bool 409 double_int::operator == (double_int cst2) const 410 { 411 return low == cst2.low && high == cst2.high; 412 } 413 414 /* Returns true if CST1 != CST2. */ 415 416 inline bool 417 double_int::operator != (double_int cst2) const 418 { 419 return low != cst2.low || high != cst2.high; 420 } 421 422 /* Return number of set bits of CST. */ 423 424 inline int 425 double_int::popcount () const 426 { 427 return popcount_hwi (high) + popcount_hwi (low); 428 } 429 430 431 #ifndef GENERATOR_FILE 432 /* Conversion to and from GMP integer representations. */ 433 434 void mpz_set_double_int (mpz_t, double_int, bool); 435 double_int mpz_get_double_int (const_tree, mpz_t, bool); 436 #endif 437 438 namespace wi 439 { 440 template <> 441 struct int_traits <double_int> 442 { 443 static const enum precision_type precision_type = CONST_PRECISION; 444 static const bool host_dependent_precision = true; 445 static const unsigned int precision = HOST_BITS_PER_DOUBLE_INT; 446 static unsigned int get_precision (const double_int &); 447 static wi::storage_ref decompose (HOST_WIDE_INT *, unsigned int, 448 const double_int &); 449 }; 450 } 451 452 inline unsigned int 453 wi::int_traits <double_int>::get_precision (const double_int &) 454 { 455 return precision; 456 } 457 458 inline wi::storage_ref 459 wi::int_traits <double_int>::decompose (HOST_WIDE_INT *scratch, unsigned int p, 460 const double_int &x) 461 { 462 gcc_checking_assert (precision == p); 463 scratch[0] = x.low; 464 if ((x.high == 0 && scratch[0] >= 0) || (x.high == -1 && scratch[0] < 0)) 465 return wi::storage_ref (scratch, 1, precision); 466 scratch[1] = x.high; 467 return wi::storage_ref (scratch, 2, precision); 468 } 469 470 #endif /* DOUBLE_INT_H */ 471