1 /* Single-precision math error handling.
2 Copyright (C) 2017-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 #include "math_config.h"
20
21 #if WANT_ERRNO
22 # include <errno.h>
23 /* NOINLINE reduces code size. */
24 NOINLINE static float
with_errnof(float y,int e)25 with_errnof (float y, int e)
26 {
27 errno = e;
28 return y;
29 }
30 #else
31 # define with_errnof(x, e) (x)
32 #endif
33
34 /* NOINLINE prevents fenv semantics breaking optimizations. */
35 NOINLINE static float
xflowf(uint32_t sign,float y)36 xflowf (uint32_t sign, float y)
37 {
38 y = (sign ? -y : y) * y;
39 return with_errnof (y, ERANGE);
40 }
41
42 attribute_hidden float
__math_uflowf(uint32_t sign)43 __math_uflowf (uint32_t sign)
44 {
45 return xflowf (sign, 0x1p-95f);
46 }
47
48 #if WANT_ERRNO_UFLOW
49 /* Underflows to zero in some non-nearest rounding mode, setting errno
50 is valid even if the result is non-zero, but in the subnormal range. */
51 attribute_hidden float
__math_may_uflowf(uint32_t sign)52 __math_may_uflowf (uint32_t sign)
53 {
54 return xflowf (sign, 0x1.4p-75f);
55 }
56 #endif
57
58 attribute_hidden float
__math_oflowf(uint32_t sign)59 __math_oflowf (uint32_t sign)
60 {
61 return xflowf (sign, 0x1p97f);
62 }
63
64 attribute_hidden float
__math_divzerof(uint32_t sign)65 __math_divzerof (uint32_t sign)
66 {
67 float y = 0;
68 return with_errnof ((sign ? -1 : 1) / y, ERANGE);
69 }
70
71 attribute_hidden float
__math_invalidf(float x)72 __math_invalidf (float x)
73 {
74 float y = (x - x) / (x - x);
75 return isnan (x) ? y : with_errnof (y, EDOM);
76 }
77