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c9cf6dde | 1 | /* Set current rounding direction. |
6d7e8eda | 2 | Copyright (C) 2001-2023 Free Software Foundation, Inc. |
c9cf6dde AJ |
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 | |
59ba27a6 | 16 | License along with the GNU C Library; if not, see |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
c9cf6dde AJ |
18 | |
19 | #include <fenv.h> | |
20 | ||
21 | int | |
01238691 | 22 | __fesetround (int round) |
c9cf6dde AJ |
23 | { |
24 | unsigned short int cw; | |
25 | int mxcsr; | |
26 | ||
27 | if ((round & ~0xc00) != 0) | |
28 | /* ROUND is no valid rounding mode. */ | |
29 | return 1; | |
30 | ||
31 | /* First set the x87 FPU. */ | |
32 | asm ("fnstcw %0" : "=m" (*&cw)); | |
33 | cw &= ~0xc00; | |
34 | cw |= round; | |
35 | asm ("fldcw %0" : : "m" (*&cw)); | |
36 | ||
37 | /* And now the MSCSR register for SSE, the precision is at different bit | |
38 | positions in the different units, we need to shift it 3 bits. */ | |
39 | asm ("stmxcsr %0" : "=m" (*&mxcsr)); | |
40 | mxcsr &= ~ 0x6000; | |
41 | mxcsr |= round << 3; | |
42 | asm ("ldmxcsr %0" : : "m" (*&mxcsr)); | |
43 | ||
44 | return 0; | |
45 | } | |
01238691 JM |
46 | libm_hidden_def (__fesetround) |
47 | weak_alias (__fesetround, fesetround) | |
48 | libm_hidden_weak (fesetround) |