blob: 9cd5d75a86a2fc3ce68b34962933b625ee65cbeb (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
|
/* Set current rounding direction.
Copyright (C) 2001-2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <fenv.h>
int
fesetround (int round)
{
unsigned short int cw;
int mxcsr;
if ((round & ~0xc00) != 0)
/* ROUND is no valid rounding mode. */
return 1;
/* First set the x87 FPU. */
asm ("fnstcw %0" : "=m" (*&cw));
cw &= ~0xc00;
cw |= round;
asm ("fldcw %0" : : "m" (*&cw));
/* And now the MSCSR register for SSE, the precision is at different bit
positions in the different units, we need to shift it 3 bits. */
asm ("stmxcsr %0" : "=m" (*&mxcsr));
mxcsr &= ~ 0x6000;
mxcsr |= round << 3;
asm ("ldmxcsr %0" : : "m" (*&mxcsr));
return 0;
}
libm_hidden_def (fesetround)
|
