1/* Install given floating-point environment.
2 Copyright (C) 2004-2022 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 <fenv.h>
20#include <fpu_control.h>
21#include <arm-features.h>
22
23
24int
25__fesetenv (const fenv_t *envp)
26{
27 fpu_control_t fpscr, new_fpscr, updated_fpscr;
28
29 /* Fail if a VFP unit isn't present. */
30 if (!ARM_HAVE_VFP)
31 return 1;
32
33 _FPU_GETCW (fpscr);
34
35 if ((envp != FE_DFL_ENV) && (envp != FE_NOMASK_ENV))
36 {
37 /* The new FPSCR is valid, so don't merge the reserved flags. */
38 new_fpscr = envp->__cw;
39
40 /* Write new FPSCR if different (ignoring NZCV flags). */
41 if (((fpscr ^ new_fpscr) & ~_FPU_MASK_NZCV) != 0)
42 _FPU_SETCW (new_fpscr);
43
44 return 0;
45 }
46
47 /* Preserve the reserved FPSCR flags. */
48 new_fpscr = fpscr & _FPU_RESERVED;
49 new_fpscr |= (envp == FE_DFL_ENV) ? _FPU_DEFAULT : _FPU_IEEE;
50
51 if (((new_fpscr ^ fpscr) & ~_FPU_MASK_NZCV) != 0)
52 {
53 _FPU_SETCW (new_fpscr);
54
55 /* Not all VFP architectures support trapping exceptions, so
56 test whether the relevant bits were set and fail if not. */
57 _FPU_GETCW (updated_fpscr);
58
59 return new_fpscr & ~updated_fpscr;
60 }
61
62 return 0;
63}
64libm_hidden_def (__fesetenv)
65weak_alias (__fesetenv, fesetenv)
66libm_hidden_weak (fesetenv)
67

source code of glibc/sysdeps/arm/fesetenv.c