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b2cb5e02 PD |
1 | /* Round to nearest integer value, rounding halfway cases to even. |
2 | Copyright (C) 2017-2018 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 | <http://www.gnu.org/licenses/>. */ | |
18 | ||
19 | #include <math.h> | |
20 | #include <math_private.h> | |
70e2ba33 | 21 | #include <fenv_private.h> |
b2cb5e02 PD |
22 | #include <libm-alias-double.h> |
23 | #include <stdint.h> | |
24 | ||
25 | double | |
26 | __roundeven (double x) | |
27 | { | |
28 | int flags = riscv_getflags (); | |
29 | bool nan = isnan (x); | |
30 | double mag = fabs (x); | |
31 | ||
32 | if (nan) | |
33 | return x + x; | |
34 | ||
35 | if (mag < (1ULL << __DBL_MANT_DIG__)) | |
36 | { | |
37 | int64_t i; | |
38 | double new_x; | |
39 | ||
40 | asm volatile ("fcvt.l.d %0, %1, rne" : "=r" (i) : "f" (x)); | |
41 | asm volatile ("fcvt.d.l %0, %1, rne" : "=f" (new_x) : "r" (i)); | |
42 | ||
43 | /* roundeven(-0) == -0, and in general we'll always have the same | |
44 | sign as our input. */ | |
45 | x = copysign (new_x, x); | |
46 | ||
47 | riscv_setflags (flags); | |
48 | } | |
49 | ||
50 | return x; | |
51 | } | |
52 | ||
53 | hidden_def (__roundeven) | |
54 | libm_alias_double (__roundeven, roundeven) |