1 /*
2 * Double-precision math error handling.
3 *
4 * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 * See https://llvm.org/LICENSE.txt for license information.
6 * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 */
8
9 #include "math_config.h"
10
11 #if WANT_ERRNO
12 #include <errno.h>
13 /* NOINLINE reduces code size and avoids making math functions non-leaf
14 when the error handling is inlined. */
15 NOINLINE static double
with_errno(double y,int e)16 with_errno (double y, int e)
17 {
18 errno = e;
19 return y;
20 }
21 #else
22 #define with_errno(x, e) (x)
23 #endif
24
25 /* NOINLINE reduces code size. */
26 NOINLINE static double
xflow(uint32_t sign,double y)27 xflow (uint32_t sign, double y)
28 {
29 y = eval_as_double (opt_barrier_double (sign ? -y : y) * y);
30 return with_errno (y, ERANGE);
31 }
32
33 HIDDEN double
__math_uflow(uint32_t sign)34 __math_uflow (uint32_t sign)
35 {
36 return xflow (sign, 0x1p-767);
37 }
38
39 #if WANT_ERRNO_UFLOW
40 /* Underflows to zero in some non-nearest rounding mode, setting errno
41 is valid even if the result is non-zero, but in the subnormal range. */
42 HIDDEN double
__math_may_uflow(uint32_t sign)43 __math_may_uflow (uint32_t sign)
44 {
45 return xflow (sign, 0x1.8p-538);
46 }
47 #endif
48
49 HIDDEN double
__math_oflow(uint32_t sign)50 __math_oflow (uint32_t sign)
51 {
52 return xflow (sign, 0x1p769);
53 }
54
55 HIDDEN double
__math_divzero(uint32_t sign)56 __math_divzero (uint32_t sign)
57 {
58 double y = opt_barrier_double (sign ? -1.0 : 1.0) / 0.0;
59 return with_errno (y, ERANGE);
60 }
61
62 HIDDEN double
__math_invalid(double x)63 __math_invalid (double x)
64 {
65 double y = (x - x) / (x - x);
66 return isnan (x) ? y : with_errno (y, EDOM);
67 }
68
69 /* Check result and set errno if necessary. */
70
71 HIDDEN double
__math_check_uflow(double y)72 __math_check_uflow (double y)
73 {
74 return y == 0.0 ? with_errno (y, ERANGE) : y;
75 }
76
77 HIDDEN double
__math_check_oflow(double y)78 __math_check_oflow (double y)
79 {
80 return isinf (y) ? with_errno (y, ERANGE) : y;
81 }
82