1 /*
2 * Copyright © 2005-2014 Rich Felker, et al.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
18 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
19 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
20 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
21 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22 */
23
24 #include "math_config.h"
25
26 // This is only necessary because the implementation of isnan only works
27 // properly when long double == double.
28 // See: https://sourceware.org/ml/newlib/2014/msg00684.html
29
30 #if !defined(_NEED_FLOAT_HUGE)
31
32 float
nexttowardf(float x,long double y)33 nexttowardf (float x, long double y)
34 {
35 uint32_t ux;
36 uint32_t e;
37
38 /*
39 * We can't do this if y isn't nan as that might raise INEXACT doing
40 * long double -> float conversion, and we don't want to do this
41 * in long double for machines without long double HW as we won't
42 * get any exceptions in that case.
43 */
44 if (isnan(y))
45 return x + (issignaling(y) ? __builtin_nansf("") : (float) y);
46 if (isnan(x))
47 return x + x;
48
49 if ((long double) x == y)
50 return (float) y;
51 ux = asuint(x);
52 if (x == 0) {
53 ux = 1;
54 if (signbit(y))
55 ux |= 0x80000000;
56 x = asfloat(ux);
57 force_eval_float(opt_barrier_float(x) * x);
58 return x;
59 } else if ((long double) x < y) {
60 if (signbit(x))
61 ux--;
62 else
63 ux++;
64 } else {
65 if (signbit(x))
66 ux++;
67 else
68 ux--;
69 }
70 e = ux & 0x7f800000;
71 /* raise overflow if ux.value is infinite and x is finite */
72 if (e == 0x7f800000)
73 return check_oflowf(opt_barrier_float(x+x));
74 /* raise underflow if ux.value is subnormal or zero */
75 x = asfloat(ux);
76 if (e == 0)
77 return __math_denormf(x);
78 return x;
79 }
80
81 _MATH_ALIAS_f_fl(nexttoward)
82
83 #endif /* _NEED_FLOAT_HUGE */
84
