1 /* Operations with long integers.
2 Copyright (C) 2006-2016 Free Software Foundation, Inc.
4 This file is part of GCC.
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
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
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/>. */
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.
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.
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. */
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. */
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);
62 /* Construct from a fuffer of length LEN. BUFFER will be read according
63 to byte endianess and word endianess. */
64 static double_int from_buffer (const unsigned char *buffer, int len);
66 /* No copy assignment operator or destructor to keep the type a POD. */
68 /* There are some special value-creation static member functions. */
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);
74 /* The following functions are mutating operations. */
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);
85 /* The following functions are non-mutating operations. */
87 /* Conversion functions. */
89 HOST_WIDE_INT to_shwi () const;
90 unsigned HOST_WIDE_INT to_uhwi () const;
92 /* Conversion query functions. */
94 bool fits_uhwi () const;
95 bool fits_shwi () const;
96 bool fits_hwi (bool uns) const;
98 /* Attribute query functions. */
100 int trailing_zeros () const;
101 int popcount () const;
103 /* Arithmetic query operations. */
105 bool multiple_of (double_int, bool, double_int *) const;
107 /* Arithmetic operation functions. */
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. */
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;
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;
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;
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. */
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;
158 /* Precision control functions. */
160 double_int ext (unsigned prec, bool uns) const;
161 double_int zext (unsigned prec) const;
162 double_int sext (unsigned prec) const;
164 /* Comparative functions. */
166 bool is_zero () const;
167 bool is_one () const;
168 bool is_minus_one () const;
169 bool is_negative () const;
171 int cmp (double_int b, bool uns) const;
172 int ucmp (double_int b) const;
173 int scmp (double_int b) const;
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;
182 double_int max (double_int b, bool uns);
183 double_int smax (double_int b);
184 double_int umax (double_int b);
186 double_int min (double_int b, bool uns);
187 double_int smin (double_int b);
188 double_int umin (double_int b);
190 bool operator == (double_int cst2) const;
191 bool operator != (double_int cst2) const;
193 /* Please migrate away from using these member variables publicly. */
195 unsigned HOST_WIDE_INT low;
200 #define HOST_BITS_PER_DOUBLE_INT (2 * HOST_BITS_PER_WIDE_INT)
202 /* Constructors and conversions. */
204 /* Constructs double_int from integer CST. The bits over the precision of
205 HOST_WIDE_INT are filled with the sign bit. */
208 double_int::from_shwi (HOST_WIDE_INT cst)
211 r.low = (unsigned HOST_WIDE_INT) cst;
212 r.high = cst < 0 ? -1 : 0;
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. */
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))
227 /* Constructs double_int from unsigned integer CST. The bits over the
228 precision of HOST_WIDE_INT are filled with zeros. */
231 double_int::from_uhwi (unsigned HOST_WIDE_INT cst)
240 double_int::from_pair (HOST_WIDE_INT high, unsigned HOST_WIDE_INT low)
249 double_int::operator ++ ()
251 *this += double_int_one;
256 double_int::operator -- ()
258 *this -= double_int_one;
263 double_int::operator &= (double_int b)
270 double_int::operator ^= (double_int b)
277 double_int::operator |= (double_int b)
283 /* Returns value of CST as a signed number. CST must satisfy
284 double_int::fits_signed. */
287 double_int::to_shwi () const
289 return (HOST_WIDE_INT) low;
292 /* Returns value of CST as an unsigned number. CST must satisfy
293 double_int::fits_unsigned. */
295 inline unsigned HOST_WIDE_INT
296 double_int::to_uhwi () const
301 /* Returns true if CST fits in unsigned HOST_WIDE_INT. */
304 double_int::fits_uhwi () const
309 /* Logical operations. */
314 double_int::operator ~ () const
325 double_int::operator | (double_int b) const
328 result.low = low | b.low;
329 result.high = high | b.high;
336 double_int::operator & (double_int b) const
339 result.low = low & b.low;
340 result.high = high & b.high;
344 /* Returns A & ~B. */
347 double_int::and_not (double_int b) const
350 result.low = low & ~b.low;
351 result.high = high & ~b.high;
358 double_int::operator ^ (double_int b) const
361 result.low = low ^ b.low;
362 result.high = high ^ b.high;
366 void dump_double_int (FILE *, double_int, bool);
368 #define ALL_ONES (~((unsigned HOST_WIDE_INT) 0))
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. */
374 /* Returns true if CST is zero. */
377 double_int::is_zero () const
379 return low == 0 && high == 0;
382 /* Returns true if CST is one. */
385 double_int::is_one () const
387 return low == 1 && high == 0;
390 /* Returns true if CST is minus one. */
393 double_int::is_minus_one () const
395 return low == ALL_ONES && high == -1;
398 /* Returns true if CST is negative. */
401 double_int::is_negative () const
406 /* Returns true if CST1 == CST2. */
409 double_int::operator == (double_int cst2) const
411 return low == cst2.low && high == cst2.high;
414 /* Returns true if CST1 != CST2. */
417 double_int::operator != (double_int cst2) const
419 return low != cst2.low || high != cst2.high;
422 /* Return number of set bits of CST. */
425 double_int::popcount () const
427 return popcount_hwi (high) + popcount_hwi (low);
431 #ifndef GENERATOR_FILE
432 /* Conversion to and from GMP integer representations. */
434 void mpz_set_double_int (mpz_t, double_int, bool);
435 double_int mpz_get_double_int (const_tree, mpz_t, bool);
441 struct int_traits <double_int>
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,
453 wi::int_traits <double_int>::get_precision (const double_int &)
458 inline wi::storage_ref
459 wi::int_traits <double_int>::decompose (HOST_WIDE_INT *scratch, unsigned int p,
462 gcc_checking_assert (precision == p);
464 if ((x.high == 0 && scratch[0] >= 0) || (x.high == -1 && scratch[0] < 0))
465 return wi::storage_ref (scratch, 1, precision);
467 return wi::storage_ref (scratch, 2, precision);
470 #endif /* DOUBLE_INT_H */