1 /* $NetBSD: t_round.c,v 1.10 2024/02/02 22:39:09 andvar Exp $ */
2
3 /*-
4 * Copyright (c) 2011 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include <sys/param.h>
30
31 #include <atf-c.h>
32 #include <float.h>
33 #include <math.h>
34 #include <stdio.h>
35 #include <stdint.h>
36
37 /*
38 * This tests for a bug in the initial implementation where
39 * precision was lost in an internal subtraction, leading to
40 * rounding into the wrong direction.
41 */
42
43 /* 0.5 - EPSILON */
44 #define VAL 0x0.7ffffffffffffcp0
45 #define VALF 0x0.7fffff8p0
46 #define VALL (0.5 - LDBL_EPSILON)
47
48 #ifdef __vax__
49 #define SMALL_NUM 1.0e-38
50 #else
51 #define SMALL_NUM 1.0e-40
52 #endif
53
54 ATF_TC(round_dir);
ATF_TC_HEAD(round_dir,tc)55 ATF_TC_HEAD(round_dir, tc)
56 {
57 atf_tc_set_md_var(tc, "descr","Check for rounding in wrong direction");
58 }
59
ATF_TC_BODY(round_dir,tc)60 ATF_TC_BODY(round_dir, tc)
61 {
62 double a = VAL, b, c;
63 float af = VALF, bf, cf;
64 long double al = VALL, bl, cl;
65
66 b = round(a);
67 bf = roundf(af);
68 bl = roundl(al);
69
70 ATF_CHECK(fabs(b) < SMALL_NUM);
71 ATF_CHECK(fabsf(bf) < SMALL_NUM);
72 ATF_CHECK(fabsl(bl) < SMALL_NUM);
73
74 c = round(-a);
75 cf = roundf(-af);
76 cl = roundl(-al);
77
78 ATF_CHECK(fabs(c) < SMALL_NUM);
79 ATF_CHECK(fabsf(cf) < SMALL_NUM);
80 ATF_CHECK(fabsl(cl) < SMALL_NUM);
81 }
82
83 ATF_TC(rounding_alpha);
ATF_TC_HEAD(rounding_alpha,tc)84 ATF_TC_HEAD(rounding_alpha, tc)
85 {
86 atf_tc_set_md_var(tc, "descr","Checking MPFR's config failure with -mieee on Alpha");
87 }
88
89 typedef uint64_t gimpy_limb_t;
90 #define GIMPY_NUMB_BITS 64
91
ATF_TC_BODY(rounding_alpha,tc)92 ATF_TC_BODY(rounding_alpha, tc)
93 {
94 double d;
95 gimpy_limb_t u;
96 int i;
97
98 d = 1.0;
99 for (i = 0; i < GIMPY_NUMB_BITS - 1; i++)
100 d = d + d;
101
102 printf("d = %g\n", d);
103 u = (gimpy_limb_t) d;
104
105 for (; i > 0; i--) {
106 ATF_CHECK_MSG((u % 2 == 0),
107 "%"PRIu64" is not an even number! (iteration %d)", u , i);
108 u = u >> 1;
109 }
110 }
111
112 ATF_TC(rounding_alpha_simple);
ATF_TC_HEAD(rounding_alpha_simple,tc)113 ATF_TC_HEAD(rounding_alpha_simple, tc)
114 {
115 atf_tc_set_md_var(tc, "descr","Checking double to uint64_t edge case");
116 }
117
118
119 double rounding_alpha_simple_even = 9223372036854775808.000000; /* 2^63 */
120
ATF_TC_BODY(rounding_alpha_simple,tc)121 ATF_TC_BODY(rounding_alpha_simple, tc)
122 {
123 uint64_t unsigned_even = rounding_alpha_simple_even;
124
125 ATF_CHECK_MSG(unsigned_even % 2 == 0,
126 "2^63 cast to uint64_t is odd (got %"PRIu64")", unsigned_even);
127
128 }
ATF_TP_ADD_TCS(tp)129 ATF_TP_ADD_TCS(tp)
130 {
131
132 ATF_TP_ADD_TC(tp, round_dir);
133 ATF_TP_ADD_TC(tp, rounding_alpha);
134 ATF_TP_ADD_TC(tp, rounding_alpha_simple);
135
136 return atf_no_error();
137 }
138