intmath.hh revision 2665:a124942bacb8 
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 __INTMATH_HH__
32#define __INTMATH_HH__
33
34#include <assert.h>
35
36#include "sim/host.hh"
37
38// Returns the prime number one less than n.
39int prevPrime(int n);
40
41// Determine if a number is prime
42template <class T>
43inline bool
44isPrime(T n)
45{
46    T i;
47
48    if (n == 2 || n == 3)
49        return true;
50
51    // Don't try every odd number to prove if it is a prime.
52    // Toggle between every 2nd and 4th number.
53    // (This is because every 6th odd number is divisible by 3.)
54    for (i = 5; i*i <= n; i += 6) {
55        if (((n % i) == 0 ) || ((n % (i + 2)) == 0) ) {
56            return false;
57        }
58    }
59
60    return true;
61}
62
63template <class T>
64inline T
65leastSigBit(T n)
66{
67    return n & ~(n - 1);
68}
69
70template <class T>
71inline bool
72isPowerOf2(T n)
73{
74    return n != 0 && leastSigBit(n) == n;
75}
76
77inline int
78floorLog2(unsigned x)
79{
80    assert(x > 0);
81
82    int y = 0;
83
84    if (x & 0xffff0000) { y += 16; x >>= 16; }
85    if (x & 0x0000ff00) { y +=  8; x >>=  8; }
86    if (x & 0x000000f0) { y +=  4; x >>=  4; }
87    if (x & 0x0000000c) { y +=  2; x >>=  2; }
88    if (x & 0x00000002) { y +=  1; }
89
90    return y;
91}
92
93inline int
94floorLog2(unsigned long x)
95{
96    assert(x > 0);
97
98    int y = 0;
99
100#if defined(__LP64__)
101    if (x & ULL(0xffffffff00000000)) { y += 32; x >>= 32; }
102#endif
103    if (x & 0xffff0000) { y += 16; x >>= 16; }
104    if (x & 0x0000ff00) { y +=  8; x >>=  8; }
105    if (x & 0x000000f0) { y +=  4; x >>=  4; }
106    if (x & 0x0000000c) { y +=  2; x >>=  2; }
107    if (x & 0x00000002) { y +=  1; }
108
109    return y;
110}
111
112inline int
113floorLog2(unsigned long long x)
114{
115    assert(x > 0);
116
117    int y = 0;
118
119    if (x & ULL(0xffffffff00000000)) { y += 32; x >>= 32; }
120    if (x & ULL(0x00000000ffff0000)) { y += 16; x >>= 16; }
121    if (x & ULL(0x000000000000ff00)) { y +=  8; x >>=  8; }
122    if (x & ULL(0x00000000000000f0)) { y +=  4; x >>=  4; }
123    if (x & ULL(0x000000000000000c)) { y +=  2; x >>=  2; }
124    if (x & ULL(0x0000000000000002)) { y +=  1; }
125
126    return y;
127}
128
129inline int
130floorLog2(int x)
131{
132    assert(x > 0);
133    return floorLog2((unsigned)x);
134}
135
136inline int
137floorLog2(long x)
138{
139    assert(x > 0);
140    return floorLog2((unsigned long)x);
141}
142
143inline int
144floorLog2(long long x)
145{
146    assert(x > 0);
147    return floorLog2((unsigned long long)x);
148}
149
150template <class T>
151inline int
152ceilLog2(T n)
153{
154    if (n == 1)
155        return 0;
156
157    return floorLog2(n - (T)1) + 1;
158}
159
160template <class T>
161inline T
162floorPow2(T n)
163{
164    return (T)1 << floorLog2(n);
165}
166
167template <class T>
168inline T
169ceilPow2(T n)
170{
171    return (T)1 << ceilLog2(n);
172}
173
174template <class T>
175inline T
176divCeil(T a, T b)
177{
178    return (a + b - 1) / b;
179}
180
181template <class T>
182inline T
183roundUp(T val, int align)
184{
185    T mask = (T)align - 1;
186    return (val + mask) & ~mask;
187}
188
189template <class T>
190inline T
191roundDown(T val, int align)
192{
193    T mask = (T)align - 1;
194    return val & ~mask;
195}
196
197inline bool
198isHex(char c)
199{
200    return c >= '0' && c <= '9' ||
201        c >= 'A' && c <= 'F' ||
202        c >= 'a' && c <= 'f';
203}
204
205inline bool
206isOct(char c)
207{
208    return c >= '0' && c <= '7';
209}
210
211inline bool
212isDec(char c)
213{
214    return c >= '0' && c <= '9';
215}
216
217inline int
218hex2Int(char c)
219{
220  if (c >= '0' && c <= '9')
221    return (c - '0');
222
223  if (c >= 'A' && c <= 'F')
224    return (c - 'A') + 10;
225
226  if (c >= 'a' && c <= 'f')
227    return (c - 'a') + 10;
228
229  return 0;
230}
231
232#endif // __INTMATH_HH__
233