1 /* Raise given exceptions.
2    Copyright (C) 2006-2021 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 <float.h>
21 #include <math.h>
22 
23 int
__feraiseexcept(int excepts)24 __feraiseexcept (int excepts)
25 {
26   /* Raise exceptions represented by EXCEPTS.  But we must raise only one
27      signal at a time.  It is important that if the overflow/underflow
28      exception and the divide by zero exception are given at the same
29      time, the overflow/underflow exception follows the divide by zero
30      exception.
31 
32      The Coldfire FPU allows an exception to be raised by asserting
33      the associated EXC bit and then executing an arbitrary arithmetic
34      instruction.  fmove.l is classified as an arithmetic instruction
35      and suffices for this purpose.
36 
37      We therefore raise an exception by setting both the EXC and AEXC
38      bit associated with the exception (the former being 6 bits to the
39      left of the latter) and then loading the longword at (%sp) into an
40      FP register.  */
41 
42   inline void
43   raise_one_exception (int mask)
44   {
45     if (excepts & mask)
46       {
47 	int fpsr;
48 	double unused;
49 
50 	asm volatile ("fmove%.l %/fpsr,%0" : "=d" (fpsr));
51 	fpsr |= (mask << 6) | mask;
52 	asm volatile ("fmove%.l %0,%/fpsr" :: "d" (fpsr));
53 	asm volatile ("fmove%.l (%%sp),%0" : "=f" (unused));
54       }
55   }
56 
57   raise_one_exception (FE_INVALID);
58   raise_one_exception (FE_DIVBYZERO);
59   raise_one_exception (FE_OVERFLOW);
60   raise_one_exception (FE_UNDERFLOW);
61   raise_one_exception (FE_INEXACT);
62 
63   /* Success.  */
64   return 0;
65 }
66 libm_hidden_def (__feraiseexcept)
67 weak_alias (__feraiseexcept, feraiseexcept)
68 libm_hidden_weak (feraiseexcept)
69