1/*
2 * Copyright (c) 2001, 2003-2005 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Nathan Binkert
29 */
30
31#ifndef __BASE_INTMATH_HH__
32#define __BASE_INTMATH_HH__
33
34#include <cassert>
35
36#include "base/misc.hh"
37#include "base/types.hh"
38
39// Returns the prime number one less than n.
40int prevPrime(int n);
41
42// Determine if a number is prime
43template <class T>
44inline bool
45isPrime(T n)
46{
47 T i;
48
49 if (n == 2 || n == 3)
50 return true;
51
52 // Don't try every odd number to prove if it is a prime.
53 // Toggle between every 2nd and 4th number.
54 // (This is because every 6th odd number is divisible by 3.)
55 for (i = 5; i*i <= n; i += 6) {
56 if (((n % i) == 0 ) || ((n % (i + 2)) == 0) ) {
57 return false;
58 }
59 }
60
61 return true;
62}
63
64template <class T>
65inline T
66leastSigBit(T n)
67{
68 return n & ~(n - 1);
69}
70
71template <class T>
72inline bool
73isPowerOf2(T n)
74{
75 return n != 0 && leastSigBit(n) == n;
76}
77
78inline uint64_t
79power(uint32_t n, uint32_t e)
80{
81 if (e > 20)
82 warn("Warning, power() function is quite slow for large exponents\n");
83
84 if (e == 0)
85 return 1;
86
87 uint64_t result = n;
88 uint64_t old_result = 0;
89 for (int x = 1; x < e; x++) {
90 old_result = result;
91 result *= n;
92 if (old_result > result)
93 warn("power() overflowed!\n");
94 }
95 return result;
96}
97
98
99inline int
100floorLog2(unsigned x)
101{
102 assert(x > 0);
103
104 int y = 0;
105
106 if (x & 0xffff0000) { y += 16; x >>= 16; }
107 if (x & 0x0000ff00) { y += 8; x >>= 8; }
108 if (x & 0x000000f0) { y += 4; x >>= 4; }
109 if (x & 0x0000000c) { y += 2; x >>= 2; }
110 if (x & 0x00000002) { y += 1; }
111
112 return y;
113}
114
115inline int
116floorLog2(unsigned long x)
117{
118 assert(x > 0);
119
120 int y = 0;
121
122#if defined(__LP64__)
123 if (x & ULL(0xffffffff00000000)) { y += 32; x >>= 32; }
124#endif
125 if (x & 0xffff0000) { y += 16; x >>= 16; }
126 if (x & 0x0000ff00) { y += 8; x >>= 8; }
127 if (x & 0x000000f0) { y += 4; x >>= 4; }
128 if (x & 0x0000000c) { y += 2; x >>= 2; }
129 if (x & 0x00000002) { y += 1; }
130
131 return y;
132}
133
134inline int
135floorLog2(unsigned long long x)
136{
137 assert(x > 0);
138
139 int y = 0;
140
141 if (x & ULL(0xffffffff00000000)) { y += 32; x >>= 32; }
142 if (x & ULL(0x00000000ffff0000)) { y += 16; x >>= 16; }
143 if (x & ULL(0x000000000000ff00)) { y += 8; x >>= 8; }
144 if (x & ULL(0x00000000000000f0)) { y += 4; x >>= 4; }
145 if (x & ULL(0x000000000000000c)) { y += 2; x >>= 2; }
146 if (x & ULL(0x0000000000000002)) { y += 1; }
147
148 return y;
149}
150
151inline int
152floorLog2(int x)
153{
154 assert(x > 0);
155 return floorLog2((unsigned)x);
156}
157
158inline int
159floorLog2(long x)
160{
161 assert(x > 0);
162 return floorLog2((unsigned long)x);
163}
164
165inline int
166floorLog2(long long x)
167{
168 assert(x > 0);
169 return floorLog2((unsigned long long)x);
170}
171
172template <class T>
173inline int
174ceilLog2(T n)
175{
176 if (n == 1)
177 return 0;
178
179 return floorLog2(n - (T)1) + 1;
180}
181
182template <class T>
183inline T
184floorPow2(T n)
185{
186 return (T)1 << floorLog2(n);
187}
188
189template <class T>
190inline T
191ceilPow2(T n)
192{
193 return (T)1 << ceilLog2(n);
194}
195
196template <class T>
197inline T
198divCeil(T a, T b)
199{
200 return (a + b - 1) / b;
201}
202
203template <class T>
204inline T
205roundUp(T val, int align)
206{
207 T mask = (T)align - 1;
208 return (val + mask) & ~mask;
209}
210
211template <class T>
212inline T
213roundDown(T val, int align)
214{
215 T mask = (T)align - 1;
216 return val & ~mask;
217}
218
219inline bool
220isHex(char c)
221{
222 return (c >= '0' && c <= '9') ||
223 (c >= 'A' && c <= 'F') ||
224 (c >= 'a' && c <= 'f');
225}
226
227inline bool
228isOct(char c)
229{
230 return c >= '0' && c <= '7';
231}
232
233inline bool
234isDec(char c)
235{
236 return c >= '0' && c <= '9';
237}
238
239inline int
240hex2Int(char c)
241{
242 if (c >= '0' && c <= '9')
243 return (c - '0');
244
245 if (c >= 'A' && c <= 'F')
246 return (c - 'A') + 10;
247
248 if (c >= 'a' && c <= 'f')
249 return (c - 'a') + 10;
250
251 return 0;
252}
253
254#endif // __BASE_INTMATH_HH__