aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/libs/clapack/ieeeck.c
blob: 3d6f0b5834111b78fe063cf965b0de9e11b620af (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
/* ieeeck.f -- translated by f2c (version 20061008).
   You must link the resulting object file with libf2c:
	on Microsoft Windows system, link with libf2c.lib;
	on Linux or Unix systems, link with .../path/to/libf2c.a -lm
	or, if you install libf2c.a in a standard place, with -lf2c -lm
	-- in that order, at the end of the command line, as in
		cc *.o -lf2c -lm
	Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,

		http://www.netlib.org/f2c/libf2c.zip
*/

#include "f2c.h"
#include "blaswrap.h"

integer ieeeck_(integer *ispec, real *zero, real *one)
{
    /* System generated locals */
    integer ret_val;

    /* Local variables */
    real nan1, nan2, nan3, nan4, nan5, nan6, neginf, posinf, negzro, newzro;


/*  -- LAPACK auxiliary routine (version 3.2) -- */
/*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/*     November 2006 */

/*     .. Scalar Arguments .. */
/*     .. */

/*  Purpose */
/*  ======= */

/*  IEEECK is called from the ILAENV to verify that Infinity and */
/*  possibly NaN arithmetic is safe (i.e. will not trap). */

/*  Arguments */
/*  ========= */

/*  ISPEC   (input) INTEGER */
/*          Specifies whether to test just for inifinity arithmetic */
/*          or whether to test for infinity and NaN arithmetic. */
/*          = 0: Verify infinity arithmetic only. */
/*          = 1: Verify infinity and NaN arithmetic. */

/*  ZERO    (input) REAL */
/*          Must contain the value 0.0 */
/*          This is passed to prevent the compiler from optimizing */
/*          away this code. */

/*  ONE     (input) REAL */
/*          Must contain the value 1.0 */
/*          This is passed to prevent the compiler from optimizing */
/*          away this code. */

/*  RETURN VALUE:  INTEGER */
/*          = 0:  Arithmetic failed to produce the correct answers */
/*          = 1:  Arithmetic produced the correct answers */

/*     .. Local Scalars .. */
/*     .. */
/*     .. Executable Statements .. */
    ret_val = 1;

    posinf = *one / *zero;
    if (posinf <= *one) {
	ret_val = 0;
	return ret_val;
    }

    neginf = -(*one) / *zero;
    if (neginf >= *zero) {
	ret_val = 0;
	return ret_val;
    }

    negzro = *one / (neginf + *one);
    if (negzro != *zero) {
	ret_val = 0;
	return ret_val;
    }

    neginf = *one / negzro;
    if (neginf >= *zero) {
	ret_val = 0;
	return ret_val;
    }

    newzro = negzro + *zero;
    if (newzro != *zero) {
	ret_val = 0;
	return ret_val;
    }

    posinf = *one / newzro;
    if (posinf <= *one) {
	ret_val = 0;
	return ret_val;
    }

    neginf *= posinf;
    if (neginf >= *zero) {
	ret_val = 0;
	return ret_val;
    }

    posinf *= posinf;
    if (posinf <= *one) {
	ret_val = 0;
	return ret_val;
    }




/*     Return if we were only asked to check infinity arithmetic */

    if (*ispec == 0) {
	return ret_val;
    }

    nan1 = posinf + neginf;

    nan2 = posinf / neginf;

    nan3 = posinf / posinf;

    nan4 = posinf * *zero;

    nan5 = neginf * negzro;

    nan6 = nan5 * 0.f;

    if (nan1 == nan1) {
	ret_val = 0;
	return ret_val;
    }

    if (nan2 == nan2) {
	ret_val = 0;
	return ret_val;
    }

    if (nan3 == nan3) {
	ret_val = 0;
	return ret_val;
    }

    if (nan4 == nan4) {
	ret_val = 0;
	return ret_val;
    }

    if (nan5 == nan5) {
	ret_val = 0;
	return ret_val;
    }

    if (nan6 == nan6) {
	ret_val = 0;
	return ret_val;
    }

    return ret_val;
} /* ieeeck_ */