1 /* Operations with long integers. 2 Copyright (C) 2006-2015 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 #include "wide-int.h" 24 25 /* A large integer is currently represented as a pair of HOST_WIDE_INTs. 26 It therefore represents a number with precision of 27 2 * HOST_BITS_PER_WIDE_INT bits (it is however possible that the 28 internal representation will change, if numbers with greater precision 29 are needed, so the users should not rely on it). The representation does 30 not contain any information about signedness of the represented value, so 31 it can be used to represent both signed and unsigned numbers. For 32 operations where the results depend on signedness (division, comparisons), 33 it must be specified separately. For each such operation, there are three 34 versions of the function -- double_int_op, that takes an extra UNS argument 35 giving the signedness of the values, and double_int_sop and double_int_uop 36 that stand for its specializations for signed and unsigned values. 37 38 You may also represent with numbers in smaller precision using double_int. 39 You however need to use double_int_ext (that fills in the bits of the 40 number over the prescribed precision with zeros or with the sign bit) before 41 operations that do not perform arithmetics modulo 2^precision (comparisons, 42 division), and possibly before storing the results, if you want to keep 43 them in some canonical form). In general, the signedness of double_int_ext 44 should match the signedness of the operation. 45 46 ??? The components of double_int differ in signedness mostly for 47 historical reasons (they replace an older structure used to represent 48 numbers with precision higher than HOST_WIDE_INT). It might be less 49 confusing to have them both signed or both unsigned. */ 50 51 struct double_int 52 { 53 /* Normally, we would define constructors to create instances. 54 Two things prevent us from doing so. 55 First, defining a constructor makes the class non-POD in C++03, 56 and we certainly want double_int to be a POD. 57 Second, the GCC conding conventions prefer explicit conversion, 58 and explicit conversion operators are not available until C++11. */ 59 60 static double_int from_uhwi (unsigned HOST_WIDE_INT cst); 61 static double_int from_shwi (HOST_WIDE_INT cst); 62 static double_int from_pair (HOST_WIDE_INT high, unsigned HOST_WIDE_INT low); 63 64 /* Construct from a fuffer of length LEN. BUFFER will be read according 65 to byte endianess and word endianess. */ 66 static double_int from_buffer (const unsigned char *buffer, int len); 67 68 /* No copy assignment operator or destructor to keep the type a POD. */ 69 70 /* There are some special value-creation static member functions. */ 71 72 static double_int mask (unsigned prec); 73 static double_int max_value (unsigned int prec, bool uns); 74 static double_int min_value (unsigned int prec, bool uns); 75 76 /* The following functions are mutating operations. */ 77 78 double_int &operator ++ (); // prefix 79 double_int &operator -- (); // prefix 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 double_int &operator ^= (double_int); 85 double_int &operator |= (double_int); 86 87 /* The following functions are non-mutating operations. */ 88 89 /* Conversion functions. */ 90 91 HOST_WIDE_INT to_shwi () const; 92 unsigned HOST_WIDE_INT to_uhwi () const; 93 94 /* Conversion query functions. */ 95 96 bool fits_uhwi () const; 97 bool fits_shwi () const; 98 bool fits_hwi (bool uns) const; 99 100 /* Attribute query functions. */ 101 102 int trailing_zeros () const; 103 int popcount () const; 104 105 /* Arithmetic query operations. */ 106 107 bool multiple_of (double_int, bool, double_int *) const; 108 109 /* Arithmetic operation functions. */ 110 111 /* The following operations perform arithmetics modulo 2^precision, so you 112 do not need to call .ext between them, even if you are representing 113 numbers with precision less than HOST_BITS_PER_DOUBLE_INT bits. */ 114 115 double_int set_bit (unsigned) const; 116 double_int mul_with_sign (double_int, bool unsigned_p, bool *overflow) const; 117 double_int wide_mul_with_sign (double_int, bool unsigned_p, 118 double_int *higher, bool *overflow) const; 119 double_int add_with_sign (double_int, bool unsigned_p, bool *overflow) const; 120 double_int sub_with_overflow (double_int, bool *overflow) const; 121 double_int neg_with_overflow (bool *overflow) const; 122 123 double_int operator * (double_int) const; 124 double_int operator + (double_int) const; 125 double_int operator - (double_int) const; 126 double_int operator - () const; 127 double_int operator ~ () const; 128 double_int operator & (double_int) const; 129 double_int operator | (double_int) const; 130 double_int operator ^ (double_int) const; 131 double_int and_not (double_int) const; 132 133 double_int lshift (HOST_WIDE_INT count) const; 134 double_int lshift (HOST_WIDE_INT count, unsigned int prec, bool arith) const; 135 double_int rshift (HOST_WIDE_INT count) const; 136 double_int rshift (HOST_WIDE_INT count, unsigned int prec, bool arith) const; 137 double_int alshift (HOST_WIDE_INT count, unsigned int prec) const; 138 double_int arshift (HOST_WIDE_INT count, unsigned int prec) const; 139 double_int llshift (HOST_WIDE_INT count, unsigned int prec) const; 140 double_int lrshift (HOST_WIDE_INT count, unsigned int prec) const; 141 double_int lrotate (HOST_WIDE_INT count, unsigned int prec) const; 142 double_int rrotate (HOST_WIDE_INT count, unsigned int prec) const; 143 144 /* You must ensure that double_int::ext is called on the operands 145 of the following operations, if the precision of the numbers 146 is less than HOST_BITS_PER_DOUBLE_INT bits. */ 147 148 double_int div (double_int, bool, unsigned) const; 149 double_int sdiv (double_int, unsigned) const; 150 double_int udiv (double_int, unsigned) const; 151 double_int mod (double_int, bool, unsigned) const; 152 double_int smod (double_int, unsigned) const; 153 double_int umod (double_int, unsigned) const; 154 double_int divmod_with_overflow (double_int, bool, unsigned, 155 double_int *, bool *) const; 156 double_int divmod (double_int, bool, unsigned, double_int *) const; 157 double_int sdivmod (double_int, unsigned, double_int *) const; 158 double_int udivmod (double_int, unsigned, double_int *) const; 159 160 /* Precision control functions. */ 161 162 double_int ext (unsigned prec, bool uns) const; 163 double_int zext (unsigned prec) const; 164 double_int sext (unsigned prec) const; 165 166 /* Comparative functions. */ 167 168 bool is_zero () const; 169 bool is_one () const; 170 bool is_minus_one () const; 171 bool is_negative () const; 172 173 int cmp (double_int b, bool uns) const; 174 int ucmp (double_int b) const; 175 int scmp (double_int b) const; 176 177 bool ult (double_int b) const; 178 bool ule (double_int b) const; 179 bool ugt (double_int b) const; 180 bool slt (double_int b) const; 181 bool sle (double_int b) const; 182 bool sgt (double_int b) const; 183 184 double_int max (double_int b, bool uns); 185 double_int smax (double_int b); 186 double_int umax (double_int b); 187 188 double_int min (double_int b, bool uns); 189 double_int smin (double_int b); 190 double_int umin (double_int b); 191 192 bool operator == (double_int cst2) const; 193 bool operator != (double_int cst2) const; 194 195 /* Please migrate away from using these member variables publicly. */ 196 197 unsigned HOST_WIDE_INT low; 198 HOST_WIDE_INT high; 199 200 }; 201 202 #define HOST_BITS_PER_DOUBLE_INT (2 * HOST_BITS_PER_WIDE_INT) 203 204 /* Constructors and conversions. */ 205 206 /* Constructs double_int from integer CST. The bits over the precision of 207 HOST_WIDE_INT are filled with the sign bit. */ 208 209 inline double_int 210 double_int::from_shwi (HOST_WIDE_INT cst) 211 { 212 double_int r; 213 r.low = (unsigned HOST_WIDE_INT) cst; 214 r.high = cst < 0 ? -1 : 0; 215 return r; 216 } 217 218 /* Some useful constants. */ 219 /* FIXME(crowl): Maybe remove after converting callers? 220 The problem is that a named constant would not be as optimizable, 221 while the functional syntax is more verbose. */ 222 223 #define double_int_minus_one (double_int::from_shwi (-1)) 224 #define double_int_zero (double_int::from_shwi (0)) 225 #define double_int_one (double_int::from_shwi (1)) 226 #define double_int_two (double_int::from_shwi (2)) 227 #define double_int_ten (double_int::from_shwi (10)) 228 229 /* Constructs double_int from unsigned integer CST. The bits over the 230 precision of HOST_WIDE_INT are filled with zeros. */ 231 232 inline double_int 233 double_int::from_uhwi (unsigned HOST_WIDE_INT cst) 234 { 235 double_int r; 236 r.low = cst; 237 r.high = 0; 238 return r; 239 } 240 241 inline double_int 242 double_int::from_pair (HOST_WIDE_INT high, unsigned HOST_WIDE_INT low) 243 { 244 double_int r; 245 r.low = low; 246 r.high = high; 247 return r; 248 } 249 250 inline double_int & 251 double_int::operator ++ () 252 { 253 *this += double_int_one; 254 return *this; 255 } 256 257 inline double_int & 258 double_int::operator -- () 259 { 260 *this -= double_int_one; 261 return *this; 262 } 263 264 inline double_int & 265 double_int::operator &= (double_int b) 266 { 267 *this = *this & b; 268 return *this; 269 } 270 271 inline double_int & 272 double_int::operator ^= (double_int b) 273 { 274 *this = *this ^ b; 275 return *this; 276 } 277 278 inline double_int & 279 double_int::operator |= (double_int b) 280 { 281 *this = *this | b; 282 return *this; 283 } 284 285 /* Returns value of CST as a signed number. CST must satisfy 286 double_int::fits_signed. */ 287 288 inline HOST_WIDE_INT 289 double_int::to_shwi () const 290 { 291 return (HOST_WIDE_INT) low; 292 } 293 294 /* Returns value of CST as an unsigned number. CST must satisfy 295 double_int::fits_unsigned. */ 296 297 inline unsigned HOST_WIDE_INT 298 double_int::to_uhwi () const 299 { 300 return low; 301 } 302 303 /* Returns true if CST fits in unsigned HOST_WIDE_INT. */ 304 305 inline bool 306 double_int::fits_uhwi () const 307 { 308 return high == 0; 309 } 310 311 /* Logical operations. */ 312 313 /* Returns ~A. */ 314 315 inline double_int 316 double_int::operator ~ () const 317 { 318 double_int result; 319 result.low = ~low; 320 result.high = ~high; 321 return result; 322 } 323 324 /* Returns A | B. */ 325 326 inline double_int 327 double_int::operator | (double_int b) const 328 { 329 double_int result; 330 result.low = low | b.low; 331 result.high = high | b.high; 332 return result; 333 } 334 335 /* Returns A & B. */ 336 337 inline double_int 338 double_int::operator & (double_int b) const 339 { 340 double_int result; 341 result.low = low & b.low; 342 result.high = high & b.high; 343 return result; 344 } 345 346 /* Returns A & ~B. */ 347 348 inline double_int 349 double_int::and_not (double_int b) const 350 { 351 double_int result; 352 result.low = low & ~b.low; 353 result.high = high & ~b.high; 354 return result; 355 } 356 357 /* Returns A ^ B. */ 358 359 inline double_int 360 double_int::operator ^ (double_int b) const 361 { 362 double_int result; 363 result.low = low ^ b.low; 364 result.high = high ^ b.high; 365 return result; 366 } 367 368 void dump_double_int (FILE *, double_int, bool); 369 370 #define ALL_ONES (~((unsigned HOST_WIDE_INT) 0)) 371 372 /* The operands of the following comparison functions must be processed 373 with double_int_ext, if their precision is less than 374 HOST_BITS_PER_DOUBLE_INT bits. */ 375 376 /* Returns true if CST is zero. */ 377 378 inline bool 379 double_int::is_zero () const 380 { 381 return low == 0 && high == 0; 382 } 383 384 /* Returns true if CST is one. */ 385 386 inline bool 387 double_int::is_one () const 388 { 389 return low == 1 && high == 0; 390 } 391 392 /* Returns true if CST is minus one. */ 393 394 inline bool 395 double_int::is_minus_one () const 396 { 397 return low == ALL_ONES && high == -1; 398 } 399 400 /* Returns true if CST is negative. */ 401 402 inline bool 403 double_int::is_negative () const 404 { 405 return high < 0; 406 } 407 408 /* Returns true if CST1 == CST2. */ 409 410 inline bool 411 double_int::operator == (double_int cst2) const 412 { 413 return low == cst2.low && high == cst2.high; 414 } 415 416 /* Returns true if CST1 != CST2. */ 417 418 inline bool 419 double_int::operator != (double_int cst2) const 420 { 421 return low != cst2.low || high != cst2.high; 422 } 423 424 /* Return number of set bits of CST. */ 425 426 inline int 427 double_int::popcount () const 428 { 429 return popcount_hwi (high) + popcount_hwi (low); 430 } 431 432 433 #ifndef GENERATOR_FILE 434 /* Conversion to and from GMP integer representations. */ 435 436 void mpz_set_double_int (mpz_t, double_int, bool); 437 double_int mpz_get_double_int (const_tree, mpz_t, bool); 438 #endif 439 440 namespace wi 441 { 442 template <> 443 struct int_traits <double_int> 444 { 445 static const enum precision_type precision_type = CONST_PRECISION; 446 static const bool host_dependent_precision = true; 447 static const unsigned int precision = HOST_BITS_PER_DOUBLE_INT; 448 static unsigned int get_precision (const double_int &); 449 static wi::storage_ref decompose (HOST_WIDE_INT *, unsigned int, 450 const double_int &); 451 }; 452 } 453 454 inline unsigned int 455 wi::int_traits <double_int>::get_precision (const double_int &) 456 { 457 return precision; 458 } 459 460 inline wi::storage_ref 461 wi::int_traits <double_int>::decompose (HOST_WIDE_INT *scratch, unsigned int p, 462 const double_int &x) 463 { 464 gcc_checking_assert (precision == p); 465 scratch[0] = x.low; 466 if ((x.high == 0 && scratch[0] >= 0) || (x.high == -1 && scratch[0] < 0)) 467 return wi::storage_ref (scratch, 1, precision); 468 scratch[1] = x.high; 469 return wi::storage_ref (scratch, 2, precision); 470 } 471 472 #endif /* DOUBLE_INT_H */ 473