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);