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      1 /* Operations with long integers.
      2    Copyright (C) 2006, 2007, 2008, 2010 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 #ifndef GENERATOR_FILE
     24 #include <gmp.h>
     25 #endif
     26 #include "coretypes.h"
     27 
     28 /* A large integer is currently represented as a pair of HOST_WIDE_INTs.
     29    It therefore represents a number with precision of
     30    2 * HOST_BITS_PER_WIDE_INT bits (it is however possible that the
     31    internal representation will change, if numbers with greater precision
     32    are needed, so the users should not rely on it).  The representation does
     33    not contain any information about signedness of the represented value, so
     34    it can be used to represent both signed and unsigned numbers.  For
     35    operations where the results depend on signedness (division, comparisons),
     36    it must be specified separately.  For each such operation, there are three
     37    versions of the function -- double_int_op, that takes an extra UNS argument
     38    giving the signedness of the values, and double_int_sop and double_int_uop
     39    that stand for its specializations for signed and unsigned values.
     40 
     41    You may also represent with numbers in smaller precision using double_int.
     42    You however need to use double_int_ext (that fills in the bits of the
     43    number over the prescribed precision with zeros or with the sign bit) before
     44    operations that do not perform arithmetics modulo 2^precision (comparisons,
     45    division), and possibly before storing the results, if you want to keep
     46    them in some canonical form).  In general, the signedness of double_int_ext
     47    should match the signedness of the operation.
     48 
     49    ??? The components of double_int differ in signedness mostly for
     50    historical reasons (they replace an older structure used to represent
     51    numbers with precision higher than HOST_WIDE_INT).  It might be less
     52    confusing to have them both signed or both unsigned.  */
     53 
     54 typedef struct
     55 {
     56   unsigned HOST_WIDE_INT low;
     57   HOST_WIDE_INT high;
     58 } double_int;
     59 
     60 #define HOST_BITS_PER_DOUBLE_INT (2 * HOST_BITS_PER_WIDE_INT)
     61 
     62 /* Constructors and conversions.  */
     63 
     64 /* Constructs double_int from integer CST.  The bits over the precision of
     65    HOST_WIDE_INT are filled with the sign bit.  */
     66 
     67 static inline double_int
     68 shwi_to_double_int (HOST_WIDE_INT cst)
     69 {
     70   double_int r;
     71 
     72   r.low = (unsigned HOST_WIDE_INT) cst;
     73   r.high = cst < 0 ? -1 : 0;
     74 
     75   return r;
     76 }
     77 
     78 /* Some useful constants.  */
     79 
     80 #define double_int_minus_one (shwi_to_double_int (-1))
     81 #define double_int_zero (shwi_to_double_int (0))
     82 #define double_int_one (shwi_to_double_int (1))
     83 #define double_int_two (shwi_to_double_int (2))
     84 #define double_int_ten (shwi_to_double_int (10))
     85 
     86 /* Constructs double_int from unsigned integer CST.  The bits over the
     87    precision of HOST_WIDE_INT are filled with zeros.  */
     88 
     89 static inline double_int
     90 uhwi_to_double_int (unsigned HOST_WIDE_INT cst)
     91 {
     92   double_int r;
     93 
     94   r.low = cst;
     95   r.high = 0;
     96 
     97   return r;
     98 }
     99 
    100 /* Returns value of CST as a signed number.  CST must satisfy
    101    double_int_fits_in_shwi_p.  */
    102 
    103 static inline HOST_WIDE_INT
    104 double_int_to_shwi (double_int cst)
    105 {
    106   return (HOST_WIDE_INT) cst.low;
    107 }
    108 
    109 /* Returns value of CST as an unsigned number.  CST must satisfy
    110    double_int_fits_in_uhwi_p.  */
    111 
    112 static inline unsigned HOST_WIDE_INT
    113 double_int_to_uhwi (double_int cst)
    114 {
    115   return cst.low;
    116 }
    117 
    118 bool double_int_fits_in_hwi_p (double_int, bool);
    119 bool double_int_fits_in_shwi_p (double_int);
    120 
    121 /* Returns true if CST fits in unsigned HOST_WIDE_INT.  */
    122 
    123 static inline bool
    124 double_int_fits_in_uhwi_p (double_int cst)
    125 {
    126   return cst.high == 0;
    127 }
    128 
    129 /* The following operations perform arithmetics modulo 2^precision,
    130    so you do not need to call double_int_ext between them, even if
    131    you are representing numbers with precision less than
    132    2 * HOST_BITS_PER_WIDE_INT bits.  */
    133 
    134 double_int double_int_mul (double_int, double_int);
    135 double_int double_int_mul_with_sign (double_int, double_int, bool, int *);
    136 double_int double_int_add (double_int, double_int);
    137 double_int double_int_sub (double_int, double_int);
    138 double_int double_int_neg (double_int);
    139 
    140 /* You must ensure that double_int_ext is called on the operands
    141    of the following operations, if the precision of the numbers
    142    is less than 2 * HOST_BITS_PER_WIDE_INT bits.  */
    143 double_int double_int_div (double_int, double_int, bool, unsigned);
    144 double_int double_int_sdiv (double_int, double_int, unsigned);
    145 double_int double_int_udiv (double_int, double_int, unsigned);
    146 double_int double_int_mod (double_int, double_int, bool, unsigned);
    147 double_int double_int_smod (double_int, double_int, unsigned);
    148 double_int double_int_umod (double_int, double_int, unsigned);
    149 double_int double_int_divmod (double_int, double_int, bool, unsigned, double_int *);
    150 double_int double_int_sdivmod (double_int, double_int, unsigned, double_int *);
    151 double_int double_int_udivmod (double_int, double_int, unsigned, double_int *);
    152 
    153 double_int double_int_setbit (double_int, unsigned);
    154 int double_int_ctz (double_int);
    155 
    156 /* Logical operations.  */
    157 
    158 /* Returns ~A.  */
    159 
    160 static inline double_int
    161 double_int_not (double_int a)
    162 {
    163   a.low = ~a.low;
    164   a.high = ~a.high;
    165   return a;
    166 }
    167 
    168 /* Returns A | B.  */
    169 
    170 static inline double_int
    171 double_int_ior (double_int a, double_int b)
    172 {
    173   a.low |= b.low;
    174   a.high |= b.high;
    175   return a;
    176 }
    177 
    178 /* Returns A & B.  */
    179 
    180 static inline double_int
    181 double_int_and (double_int a, double_int b)
    182 {
    183   a.low &= b.low;
    184   a.high &= b.high;
    185   return a;
    186 }
    187 
    188 /* Returns A & ~B.  */
    189 
    190 static inline double_int
    191 double_int_and_not (double_int a, double_int b)
    192 {
    193   a.low &= ~b.low;
    194   a.high &= ~b.high;
    195   return a;
    196 }
    197 
    198 /* Returns A ^ B.  */
    199 
    200 static inline double_int
    201 double_int_xor (double_int a, double_int b)
    202 {
    203   a.low ^= b.low;
    204   a.high ^= b.high;
    205   return a;
    206 }
    207 
    208 
    209 /* Shift operations.  */
    210 double_int double_int_lshift (double_int, HOST_WIDE_INT, unsigned int, bool);
    211 double_int double_int_rshift (double_int, HOST_WIDE_INT, unsigned int, bool);
    212 double_int double_int_lrotate (double_int, HOST_WIDE_INT, unsigned int);
    213 double_int double_int_rrotate (double_int, HOST_WIDE_INT, unsigned int);
    214 
    215 /* Returns true if CST is negative.  Of course, CST is considered to
    216    be signed.  */
    217 
    218 static inline bool
    219 double_int_negative_p (double_int cst)
    220 {
    221   return cst.high < 0;
    222 }
    223 
    224 int double_int_cmp (double_int, double_int, bool);
    225 int double_int_scmp (double_int, double_int);
    226 int double_int_ucmp (double_int, double_int);
    227 
    228 double_int double_int_max (double_int, double_int, bool);
    229 double_int double_int_smax (double_int, double_int);
    230 double_int double_int_umax (double_int, double_int);
    231 
    232 double_int double_int_min (double_int, double_int, bool);
    233 double_int double_int_smin (double_int, double_int);
    234 double_int double_int_umin (double_int, double_int);
    235 
    236 void dump_double_int (FILE *, double_int, bool);
    237 
    238 /* Zero and sign extension of numbers in smaller precisions.  */
    239 
    240 double_int double_int_ext (double_int, unsigned, bool);
    241 double_int double_int_sext (double_int, unsigned);
    242 double_int double_int_zext (double_int, unsigned);
    243 double_int double_int_mask (unsigned);
    244 
    245 #define ALL_ONES (~((unsigned HOST_WIDE_INT) 0))
    246 
    247 /* The operands of the following comparison functions must be processed
    248    with double_int_ext, if their precision is less than
    249    2 * HOST_BITS_PER_WIDE_INT bits.  */
    250 
    251 /* Returns true if CST is zero.  */
    252 
    253 static inline bool
    254 double_int_zero_p (double_int cst)
    255 {
    256   return cst.low == 0 && cst.high == 0;
    257 }
    258 
    259 /* Returns true if CST is one.  */
    260 
    261 static inline bool
    262 double_int_one_p (double_int cst)
    263 {
    264   return cst.low == 1 && cst.high == 0;
    265 }
    266 
    267 /* Returns true if CST is minus one.  */
    268 
    269 static inline bool
    270 double_int_minus_one_p (double_int cst)
    271 {
    272   return (cst.low == ALL_ONES && cst.high == -1);
    273 }
    274 
    275 /* Returns true if CST1 == CST2.  */
    276 
    277 static inline bool
    278 double_int_equal_p (double_int cst1, double_int cst2)
    279 {
    280   return cst1.low == cst2.low && cst1.high == cst2.high;
    281 }
    282 
    283 
    284 /* Legacy interface with decomposed high/low parts.  */
    285 
    286 extern int add_double_with_sign (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
    287 				 unsigned HOST_WIDE_INT, HOST_WIDE_INT,
    288 				 unsigned HOST_WIDE_INT *, HOST_WIDE_INT *,
    289 				 bool);
    290 #define add_double(l1,h1,l2,h2,lv,hv) \
    291   add_double_with_sign (l1, h1, l2, h2, lv, hv, false)
    292 extern int neg_double (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
    293 		       unsigned HOST_WIDE_INT *, HOST_WIDE_INT *);
    294 extern int mul_double_with_sign (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
    295 				 unsigned HOST_WIDE_INT, HOST_WIDE_INT,
    296 				 unsigned HOST_WIDE_INT *, HOST_WIDE_INT *,
    297 				 bool);
    298 #define mul_double(l1,h1,l2,h2,lv,hv) \
    299   mul_double_with_sign (l1, h1, l2, h2, lv, hv, false)
    300 extern void lshift_double (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
    301 			   HOST_WIDE_INT, unsigned int,
    302 			   unsigned HOST_WIDE_INT *, HOST_WIDE_INT *, bool);
    303 extern void rshift_double (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
    304 			   HOST_WIDE_INT, unsigned int,
    305 			   unsigned HOST_WIDE_INT *, HOST_WIDE_INT *, bool);
    306 extern int div_and_round_double (unsigned, int, unsigned HOST_WIDE_INT,
    307 				 HOST_WIDE_INT, unsigned HOST_WIDE_INT,
    308 				 HOST_WIDE_INT, unsigned HOST_WIDE_INT *,
    309 				 HOST_WIDE_INT *, unsigned HOST_WIDE_INT *,
    310 				 HOST_WIDE_INT *);
    311 
    312 
    313 #ifndef GENERATOR_FILE
    314 /* Conversion to and from GMP integer representations.  */
    315 
    316 void mpz_set_double_int (mpz_t, double_int, bool);
    317 double_int mpz_get_double_int (const_tree, mpz_t, bool);
    318 #endif
    319 
    320 #endif /* DOUBLE_INT_H */
    321