1 /* Operations on HOST_WIDE_INT.
2 Copyright (C) 1987-2013 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 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/>. */
22 #include "diagnostic-core.h"
24 #if GCC_VERSION < 3004
26 /* The functions clz_hwi, ctz_hwi, ffs_hwi, floor_log2, ceil_log2,
27 and exact_log2 are defined as inline functions in hwint.h
28 if GCC_VERSION >= 3004.
29 The definitions here are used for older versions of GCC and
30 non-GCC bootstrap compilers. */
32 /* Given X, an unsigned number, return the largest int Y such that 2**Y <= X.
33 If X is 0, return -1. */
36 floor_log2 (unsigned HOST_WIDE_INT x)
43 if (HOST_BITS_PER_WIDE_INT > 64)
44 if (x >= (unsigned HOST_WIDE_INT) 1 << (t + 64))
46 if (HOST_BITS_PER_WIDE_INT > 32)
47 if (x >= ((unsigned HOST_WIDE_INT) 1) << (t + 32))
49 if (x >= ((unsigned HOST_WIDE_INT) 1) << (t + 16))
51 if (x >= ((unsigned HOST_WIDE_INT) 1) << (t + 8))
53 if (x >= ((unsigned HOST_WIDE_INT) 1) << (t + 4))
55 if (x >= ((unsigned HOST_WIDE_INT) 1) << (t + 2))
57 if (x >= ((unsigned HOST_WIDE_INT) 1) << (t + 1))
63 /* Given X, an unsigned number, return the largest Y such that 2**Y >= X. */
66 ceil_log2 (unsigned HOST_WIDE_INT x)
68 return floor_log2 (x - 1) + 1;
71 /* Return the logarithm of X, base 2, considering X unsigned,
72 if X is a power of 2. Otherwise, returns -1. */
75 exact_log2 (unsigned HOST_WIDE_INT x)
79 return floor_log2 (x);
82 /* Given X, an unsigned number, return the number of least significant bits
83 that are zero. When X == 0, the result is the word size. */
86 ctz_hwi (unsigned HOST_WIDE_INT x)
88 return x ? floor_log2 (x & -x) : HOST_BITS_PER_WIDE_INT;
91 /* Similarly for most significant bits. */
94 clz_hwi (unsigned HOST_WIDE_INT x)
96 return HOST_BITS_PER_WIDE_INT - 1 - floor_log2(x);
99 /* Similar to ctz_hwi, except that the least significant bit is numbered
100 starting from 1, and X == 0 yields 0. */
103 ffs_hwi (unsigned HOST_WIDE_INT x)
105 return 1 + floor_log2 (x & -x);
108 /* Return the number of set bits in X. */
111 popcount_hwi (unsigned HOST_WIDE_INT x)
114 size_t bits = sizeof (x) * CHAR_BIT;
116 for (i = 0; i < bits; i += 1)
125 #endif /* GCC_VERSION < 3004 */
127 /* Compute the absolute value of X. */
130 abs_hwi (HOST_WIDE_INT x)
132 gcc_checking_assert (x != HOST_WIDE_INT_MIN);
133 return x >= 0 ? x : -x;
136 /* Compute the absolute value of X as an unsigned type. */
138 unsigned HOST_WIDE_INT
139 absu_hwi (HOST_WIDE_INT x)
141 return x >= 0 ? (unsigned HOST_WIDE_INT)x : -(unsigned HOST_WIDE_INT)x;
144 /* Compute the greatest common divisor of two numbers A and B using
145 Euclid's algorithm. */
148 gcd (HOST_WIDE_INT a, HOST_WIDE_INT b)
150 HOST_WIDE_INT x, y, z;
165 /* For X and Y positive integers, return X multiplied by Y and check
166 that the result does not overflow. */
169 pos_mul_hwi (HOST_WIDE_INT x, HOST_WIDE_INT y)
172 gcc_checking_assert ((HOST_WIDE_INT_MAX) / x >= y);
177 /* Return X multiplied by Y and check that the result does not
181 mul_hwi (HOST_WIDE_INT x, HOST_WIDE_INT y)
183 gcc_checking_assert (x != HOST_WIDE_INT_MIN
184 && y != HOST_WIDE_INT_MIN);
189 return pos_mul_hwi (x, y);
191 return -pos_mul_hwi (x, -y);
195 return -pos_mul_hwi (-x, y);
197 return pos_mul_hwi (-x, -y);
200 /* Compute the least common multiple of two numbers A and B . */
203 least_common_multiple (HOST_WIDE_INT a, HOST_WIDE_INT b)
205 return mul_hwi (abs_hwi (a) / gcd (a, b), abs_hwi (b));
208 #ifdef ENABLE_CHECKING
209 /* Sign extend SRC starting from PREC. */
212 sext_hwi (HOST_WIDE_INT src, unsigned int prec)
214 gcc_checking_assert (prec <= HOST_BITS_PER_WIDE_INT);
216 if (prec == HOST_BITS_PER_WIDE_INT)
220 int shift = HOST_BITS_PER_WIDE_INT - prec;
221 return (src << shift) >> shift;
225 /* Zero extend SRC starting from PREC. */
227 unsigned HOST_WIDE_INT
228 zext_hwi (unsigned HOST_WIDE_INT src, unsigned int prec)
230 gcc_checking_assert (prec <= HOST_BITS_PER_WIDE_INT);
232 if (prec == HOST_BITS_PER_WIDE_INT)
235 return src & (((HOST_WIDE_INT)1 << prec) - 1);