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38 #include "gmxpre.h"
39
40 #include "utilities.h"
41
42 #include "config.h"
43
44 #include <cassert>
45 #include <climits>
46 #include <cmath>
47
48 #include <algorithm>
49 #include <cfenv>
50
51 //! Floating point exception set that we use and care about
52 constexpr int c_FPexceptions = FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW;
53
gmx_within_tol(double f1,double f2,double tol)54 bool gmx_within_tol(double f1, double f2, double tol)
55 {
56 /* The or-equal is important - otherwise we return false if f1==f2==0 */
57 return fabs(f1 - f2) <= tol * 0.5 * (fabs(f1) + fabs(f2));
58 }
59
gmx_numzero(double a)60 bool gmx_numzero(double a)
61 {
62 return gmx_within_tol(a, 0.0, GMX_REAL_MIN / GMX_REAL_EPS);
63 }
64
65
check_int_multiply_for_overflow(int64_t a,int64_t b,int64_t * result)66 gmx_bool check_int_multiply_for_overflow(int64_t a, int64_t b, int64_t* result)
67 {
68 int64_t sign = 1;
69 if ((0 == a) || (0 == b))
70 {
71 *result = 0;
72 return TRUE;
73 }
74 if (a < 0)
75 {
76 a = -a;
77 sign = -sign;
78 }
79 if (b < 0)
80 {
81 b = -b;
82 sign = -sign;
83 }
84 if (INT64_MAX / b < a)
85 {
86 *result = (sign > 0) ? INT64_MAX : INT64_MIN;
87 return FALSE;
88 }
89 *result = sign * a * b;
90 return TRUE;
91 }
92
gmx_feenableexcept()93 int gmx_feenableexcept()
94 {
95 #if HAVE_FEENABLEEXCEPT
96 return feenableexcept(c_FPexceptions);
97 #elif (defined(__i386__) || defined(__x86_64__)) && defined(__APPLE__)
98 /* Author: David N. Williams
99 * License: Public Domain
100 *
101 * Might also work on non-Apple Unix. But should be tested
102 * before enabling.
103 */
104 static fenv_t fenv;
105 unsigned int new_excepts = c_FPexceptions & FE_ALL_EXCEPT;
106
107 if (fegetenv(&fenv))
108 {
109 return -1;
110 }
111
112 // unmask
113 fenv.__control &= ~new_excepts;
114 fenv.__mxcsr &= ~(new_excepts << 7);
115
116 return fesetenv(&fenv);
117 #else
118 return -1;
119 #endif
120 }
121
gmx_fedisableexcept()122 int gmx_fedisableexcept()
123 {
124 #if HAVE_FEDISABLEEXCEPT
125 return fedisableexcept(c_FPexceptions);
126 #elif (defined(__i386__) || defined(__x86_64__)) && defined(__APPLE__)
127 static fenv_t fenv;
128 unsigned int new_excepts = c_FPexceptions & FE_ALL_EXCEPT;
129 if (fegetenv(&fenv))
130 {
131 return -1;
132 }
133
134 // mask
135 fenv.__control |= new_excepts;
136 fenv.__mxcsr |= new_excepts << 7;
137
138 return fesetenv(&fenv);
139 #else
140 return -1;
141 #endif
142 }
143