]>
Commit | Line | Data |
---|---|---|
f82783bd ZD |
1 | /* Operations with long integers. |
2 | Copyright (C) 2006 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 2, 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 COPYING. If not, write to the Free | |
18 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA | |
19 | 02110-1301, USA. */ | |
20 | ||
21 | #ifndef DOUBLE_INT_H | |
22 | #define DOUBLE_INT_H | |
23 | ||
24 | /* A large integer is currently represented as a pair of HOST_WIDE_INTs. | |
25 | It therefore represents a number with precision of | |
26 | 2 * HOST_BITS_PER_WIDE_INT bits (it is however possible that the | |
27 | internal representation will change, if numbers with greater precision | |
28 | are needed, so the users should not rely on it). The representation does | |
29 | not contain any information about signedness of the represented value, so | |
30 | it can be used to represent both signed and unsigned numbers. For | |
31 | operations where the results depend on signedness (division, comparisons), | |
32 | it must be specified separately. For each such operation, there are three | |
33 | versions of the function -- double_int_op, that takes an extra UNS argument | |
34 | giving the signedness of the values, and double_int_sop and double_int_uop | |
35 | that stand for its specializations for signed and unsigned values. | |
36 | ||
37 | You may also represent with numbers in smaller precision using double_int. | |
38 | You however need to use double_int_ext (that fills in the bits of the | |
39 | number over the prescribed precision with zeros or with the sign bit) before | |
40 | operations that do not perform arithmetics modulo 2^precision (comparisons, | |
41 | division), and possibly before storing the results, if you want to keep | |
42 | them in some canonical form). In general, the signedness of double_int_ext | |
43 | should match the signedness of the operation. | |
44 | ||
45 | ??? The components of double_int differ in signedness mostly for | |
46 | historical reasons (they replace an older structure used to represent | |
47 | numbers with precision wigher than HOST_WIDE_INT). It might be less | |
48 | confusing to have them both signed or both unsigned. */ | |
49 | ||
50 | typedef struct | |
51 | { | |
52 | unsigned HOST_WIDE_INT low; | |
53 | HOST_WIDE_INT high; | |
54 | } double_int; | |
55 | ||
56 | union tree_node; | |
57 | ||
58 | /* Constructors and conversions. */ | |
59 | ||
60 | union tree_node *double_int_to_tree (union tree_node *, double_int); | |
61 | double_int tree_to_double_int (union tree_node *tree); | |
62 | ||
63 | /* Constructs double_int from integer CST. The bits over the precision of | |
64 | HOST_WIDE_INT are filled with the sign bit. */ | |
65 | ||
66 | static inline double_int | |
67 | shwi_to_double_int (HOST_WIDE_INT cst) | |
68 | { | |
69 | double_int r; | |
70 | ||
71 | r.low = (unsigned HOST_WIDE_INT) cst; | |
72 | r.high = cst < 0 ? -1 : 0; | |
73 | ||
74 | return r; | |
75 | } | |
76 | ||
77 | /* Some useful constants. */ | |
78 | ||
79 | #define double_int_minus_one (shwi_to_double_int (-1)) | |
80 | #define double_int_zero (shwi_to_double_int (0)) | |
81 | #define double_int_one (shwi_to_double_int (1)) | |
82 | #define double_int_two (shwi_to_double_int (2)) | |
83 | #define double_int_ten (shwi_to_double_int (10)) | |
84 | ||
85 | /* Constructs double_int from unsigned integer CST. The bits over the | |
86 | precision of HOST_WIDE_INT are filled with zeros. */ | |
87 | ||
88 | static inline double_int | |
89 | uhwi_to_double_int (unsigned HOST_WIDE_INT cst) | |
90 | { | |
91 | double_int r; | |
92 | ||
93 | r.low = cst; | |
94 | r.high = 0; | |
95 | ||
96 | return r; | |
97 | } | |
98 | ||
99 | /* The following operations perform arithmetics modulo 2^precision, | |
100 | so you do not need to call double_int_ext between them, even if | |
101 | you are representing numbers with precision less than | |
102 | 2 * HOST_BITS_PER_WIDE_INT bits. */ | |
103 | ||
104 | double_int double_int_mul (double_int, double_int); | |
105 | double_int double_int_add (double_int, double_int); | |
106 | double_int double_int_neg (double_int); | |
107 | ||
108 | /* You must ensure that double_int_ext is called on the operands | |
109 | of the following operations, if the precision of the numbers | |
110 | is less than 2 * HOST_BITS_PER_WIDE_INT bits. */ | |
111 | bool double_int_fits_in_hwi_p (double_int, bool); | |
112 | bool double_int_fits_in_shwi_p (double_int); | |
113 | bool double_int_fits_in_uhwi_p (double_int); | |
114 | HOST_WIDE_INT double_int_to_shwi (double_int); | |
115 | unsigned HOST_WIDE_INT double_int_to_uhwi (double_int); | |
116 | double_int double_int_div (double_int, double_int, bool, unsigned); | |
117 | double_int double_int_sdiv (double_int, double_int, unsigned); | |
118 | double_int double_int_udiv (double_int, double_int, unsigned); | |
119 | bool double_int_negative_p (double_int); | |
120 | int double_int_cmp (double_int, double_int, bool); | |
121 | int double_int_scmp (double_int, double_int); | |
122 | int double_int_ucmp (double_int, double_int); | |
123 | void dump_double_int (FILE *, double_int, bool); | |
124 | ||
125 | /* Zero and sign extension of numbers in smaller precisions. */ | |
126 | ||
127 | double_int double_int_ext (double_int, unsigned, bool); | |
128 | double_int double_int_sext (double_int, unsigned); | |
129 | double_int double_int_zext (double_int, unsigned); | |
130 | ||
131 | #define ALL_ONES (~((unsigned HOST_WIDE_INT) 0)) | |
132 | ||
133 | /* The operands of the following comparison functions must be processed | |
134 | with double_int_ext, if their precision is less than | |
135 | 2 * HOST_BITS_PER_WIDE_INT bits. */ | |
136 | ||
137 | /* Returns true if CST is zero. */ | |
138 | ||
139 | static inline bool | |
140 | double_int_zero_p (double_int cst) | |
141 | { | |
142 | return cst.low == 0 && cst.high == 0; | |
143 | } | |
144 | ||
145 | /* Returns true if CST is one. */ | |
146 | ||
147 | static inline bool | |
148 | double_int_one_p (double_int cst) | |
149 | { | |
150 | return cst.low == 1 && cst.high == 0; | |
151 | } | |
152 | ||
153 | /* Returns true if CST is minus one. */ | |
154 | ||
155 | static inline bool | |
156 | double_int_minus_one_p (double_int cst) | |
157 | { | |
158 | return (cst.low == ALL_ONES && cst.high == -1); | |
159 | } | |
160 | ||
161 | /* Returns true if CST1 == CST2. */ | |
162 | ||
163 | static inline bool | |
164 | double_int_equal_p (double_int cst1, double_int cst2) | |
165 | { | |
166 | return cst1.low == cst2.low && cst1.high == cst2.high; | |
167 | } | |
168 | ||
169 | #endif /* DOUBLE_INT_H */ |