KiCad PCB EDA Suite
math_util.cpp
Go to the documentation of this file.
1 /*
2  * This program source code file is part of KICAD, a free EDA CAD application.
3  *
4  * Copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
5  * Copyright (C) CERN
6  * @author Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License
10  * as published by the Free Software Foundation; either version 2
11  * of the License, or (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, you may find one here:
20  * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
21  * or you may search the http://www.gnu.org website for the version 2 license,
22  * or you may write to the Free Software Foundation, Inc.,
23  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
24  */
25 
26 #include <cmath>
27 #include <cstdlib>
28 #include <climits>
29 #include <math/math_util.h>
30 
31 template<>
32 int rescale( int aNumerator, int aValue, int aDenominator )
33 {
34  return (int) ( (int64_t) aNumerator * (int64_t) aValue / (int64_t) aDenominator );
35 }
36 
37 
38 template<>
39 int64_t rescale( int64_t aNumerator, int64_t aValue, int64_t aDenominator )
40 {
41 #ifdef __x86_64__
42  return ( (__int128_t) aNumerator * (__int128_t) aValue ) / aDenominator;
43 #else
44  int64_t r = 0;
45  int64_t sign = ( ( aNumerator < 0 ) ? -1 : 1 ) * ( aDenominator < 0 ? -1 : 1 ) *
46  ( aValue < 0 ? -1 : 1 );
47 
48  int64_t a = std::abs( aNumerator );
49  int64_t b = std::abs( aValue );
50  int64_t c = std::abs( aDenominator );
51 
52  r = c / 2;
53 
54  if( b <= INT_MAX && c <= INT_MAX )
55  {
56  if( a <= INT_MAX )
57  return sign * ( ( a * b + r ) / c );
58  else
59  return sign * ( a / c * b + ( a % c * b + r ) / c);
60  }
61  else
62  {
63  uint64_t a0 = a & 0xFFFFFFFF;
64  uint64_t a1 = a >> 32;
65  uint64_t b0 = b & 0xFFFFFFFF;
66  uint64_t b1 = b >> 32;
67  uint64_t t1 = a0 * b1 + a1 * b0;
68  uint64_t t1a = t1 << 32;
69  int i;
70 
71  a0 = a0 * b0 + t1a;
72  a1 = a1 * b1 + ( t1 >> 32 ) + ( a0 < t1a );
73  a0 += r;
74  a1 += a0 < (uint64_t)r;
75 
76  for( i = 63; i >= 0; i-- )
77  {
78  a1 += a1 + ( ( a0 >> i ) & 1 );
79  t1 += t1;
80 
81  if( (uint64_t) c <= a1 )
82  {
83  a1 -= c;
84  t1++;
85  }
86  }
87 
88  return t1 * sign;
89  }
90 #endif
91 }
#define abs(a)
Definition: auxiliary.h:84
int rescale(int aNumerator, int aValue, int aDenominator)
Definition: math_util.cpp:32
int sign(T val)
Definition: math_util.h:44