1/* Copyright (C) 1997-2022 Free Software Foundation, Inc.
2
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 License as
7 published by the Free Software Foundation; either version 2.1 of the
8 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
22int
23__fesetenv (const fenv_t *envp)
24{
25 fpu_control_t fpcr;
26 fpu_control_t fpcr_new;
27 fpu_control_t updated_fpcr;
28 fpu_fpsr_t fpsr;
29 fpu_fpsr_t fpsr_new;
30
31 _FPU_GETCW (fpcr);
32
33 if ((envp != FE_DFL_ENV) && (envp != FE_NOMASK_ENV))
34 {
35 /* The new FPCR/FPSR are valid, so don't merge the reserved flags. */
36 fpcr_new = envp->__fpcr;
37
38 if (fpcr != fpcr_new)
39 _FPU_SETCW (fpcr_new);
40
41 _FPU_SETFPSR (envp->__fpsr);
42 return 0;
43 }
44
45 _FPU_GETFPSR (fpsr);
46 fpcr_new = fpcr & _FPU_RESERVED;
47 fpsr_new = fpsr & _FPU_FPSR_RESERVED;
48
49 if (envp == FE_DFL_ENV)
50 {
51 fpcr_new |= _FPU_DEFAULT;
52 fpsr_new |= _FPU_FPSR_DEFAULT;
53 }
54 else
55 {
56 fpcr_new |= _FPU_FPCR_IEEE;
57 fpsr_new |= _FPU_FPSR_IEEE;
58 }
59
60 _FPU_SETFPSR (fpsr_new);
61
62 if (fpcr != fpcr_new)
63 {
64 _FPU_SETCW (fpcr_new);
65
66 /* Trapping exceptions are optional in AArch64; the relevant enable
67 bits in FPCR are RES0 hence the absence of support can be detected
68 by reading back the FPCR and comparing with the required value. */
69 _FPU_GETCW (updated_fpcr);
70
71 return fpcr_new & ~updated_fpcr;
72 }
73
74 return 0;
75}
76libm_hidden_def (__fesetenv)
77weak_alias (__fesetenv, fesetenv)
78libm_hidden_weak (fesetenv)
79

source code of glibc/sysdeps/aarch64/fpu/fesetenv.c