xref: /freebsd/contrib/netbsd-tests/lib/libm/t_fe_round.c (revision 1c05a6ea6b849ff95e539c31adea887c644a6a01)
1 /*
2  * Written by Maya Rashish <maya@NetBSD.org>
3  * Public domain.
4  *
5  * Testing IEEE-754 rounding modes (and lrint)
6  */
7 
8 #include <atf-c.h>
9 #include <fenv.h>
10 #ifdef __HAVE_FENV
11 #include <math.h>
12 #include <stdio.h>
13 #include <stdlib.h>
14 
15 /*#pragma STDC FENV_ACCESS ON gcc?? */
16 
17 #define INT 9223L
18 
19 #define EPSILON 0.001
20 
21 static const struct {
22 	int round_mode;
23 	double input;
24 	long int expected;
25 } values[] = {
26 	{ FE_DOWNWARD,		3.7,		3},
27 	{ FE_DOWNWARD,		-3.7,		-4},
28 	{ FE_DOWNWARD,		+0,		0},
29 	{ FE_DOWNWARD,		-INT-0.01,	-INT-1},
30 	{ FE_DOWNWARD,		+INT-0.01,	INT-1},
31 	{ FE_DOWNWARD,		-INT+0.01,	-INT},
32 	{ FE_DOWNWARD,		+INT+0.01,	INT},
33 #if 0 /* cpu bugs? */
34 	{ FE_DOWNWARD,		-0,		-1},
35 
36 	{ FE_UPWARD,		+0,		1},
37 #endif
38 	{ FE_UPWARD,		-0,		0},
39 	{ FE_UPWARD,		-123.7,		-123},
40 	{ FE_UPWARD,		123.999,	124},
41 	{ FE_UPWARD,		-INT-0.01,	-INT},
42 	{ FE_UPWARD,		+INT-0.01,	INT},
43 	{ FE_UPWARD,		-INT+0.01,	-INT+1},
44 	{ FE_UPWARD,		+INT+0.01,	INT+1},
45 
46 	{ FE_TOWARDZERO,	1.99,		1},
47 	{ FE_TOWARDZERO,	-1.99,		-1},
48 	{ FE_TOWARDZERO,	0.2,		0},
49 	{ FE_TOWARDZERO,	INT+0.01,	INT},
50 	{ FE_TOWARDZERO,	INT-0.01,	INT - 1},
51 	{ FE_TOWARDZERO,	-INT+0.01,	-INT + 1},
52 	{ FE_TOWARDZERO,	+0,		0},
53 	{ FE_TOWARDZERO,	-0,		0},
54 
55 	{ FE_TONEAREST,		-INT-0.01,	-INT},
56 	{ FE_TONEAREST,		+INT-0.01,	INT},
57 	{ FE_TONEAREST,		-INT+0.01,	-INT},
58 	{ FE_TONEAREST,		+INT+0.01,	INT},
59 	{ FE_TONEAREST,		-INT-0.501,	-INT-1},
60 	{ FE_TONEAREST,		+INT-0.501,	INT-1},
61 	{ FE_TONEAREST,		-INT+0.501,	-INT+1},
62 	{ FE_TONEAREST,		+INT+0.501,	INT+1},
63 	{ FE_TONEAREST,		+0,		0},
64 	{ FE_TONEAREST,		-0,		0},
65 };
66 
67 ATF_TC(fe_round);
68 ATF_TC_HEAD(fe_round, tc)
69 {
70 	atf_tc_set_md_var(tc, "descr","Checking IEEE 754 rounding modes using lrint");
71 }
72 
73 ATF_TC_BODY(fe_round, tc)
74 {
75 	long int received;
76 
77 	for (unsigned int i = 0; i < __arraycount(values); i++) {
78 		fesetround(values[i].round_mode);
79 
80 		received = lrint(values[i].input);
81 		ATF_CHECK_MSG(
82 		    (labs(received - values[i].expected) < EPSILON),
83 		    "lrint rounding wrong, difference too large\n"
84 		    "input: %f (index %d): got %ld, expected %ld\n",
85 		    values[i].input, i, received, values[i].expected);
86 
87 		/* Do we get the same rounding mode out? */
88 		ATF_CHECK_MSG(
89 		    (fegetround() == values[i].round_mode),
90 		    "Didn't get the same rounding mode out!\n"
91 		    "(index %d) fed in %d rounding mode, got %d out\n",
92 		    i, fegetround(), values[i].round_mode);
93 	}
94 }
95 
96 ATF_TP_ADD_TCS(tp)
97 {
98 
99 	ATF_TP_ADD_TC(tp, fe_round);
100 
101 	return atf_no_error();
102 }
103 #else
104 ATF_TC(t_nofe_round);
105 
106 ATF_TC_HEAD(t_nofe_round, tc)
107 {
108 	atf_tc_set_md_var(tc, "descr",
109 	    "dummy test case - no fenv.h support");
110 }
111 
112 
113 ATF_TC_BODY(t_nofe_round, tc)
114 {
115 	atf_tc_skip("no fenv.h support on this architecture");
116 }
117 
118 ATF_TP_ADD_TCS(tp)
119 {
120 	ATF_TP_ADD_TC(tp, t_nofe_round);
121 	return atf_no_error();
122 }
123 
124 #endif
125