1 | /* Raise given exceptions. |
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 <fpu_control.h> |
20 | #include <fenv.h> |
21 | #include <float.h> |
22 | #include <arm-features.h> |
23 | |
24 | |
25 | int |
26 | __feraiseexcept (int excepts) |
27 | { |
28 | /* Fail if a VFP unit isn't present unless nothing needs to be done. */ |
29 | if (!ARM_HAVE_VFP) |
30 | return (excepts != 0); |
31 | else |
32 | { |
33 | fpu_control_t fpscr; |
34 | const float fp_zero = 0.0, fp_one = 1.0, fp_max = FLT_MAX, |
35 | fp_min = FLT_MIN, fp_1e32 = 1.0e32f, fp_two = 2.0, |
36 | fp_three = 3.0; |
37 | |
38 | /* Raise exceptions represented by EXPECTS. But we must raise only |
39 | one signal at a time. It is important that if the overflow/underflow |
40 | exception and the inexact exception are given at the same time, |
41 | the overflow/underflow exception follows the inexact exception. After |
42 | each exception we read from the fpscr, to force the exception to be |
43 | raised immediately. */ |
44 | |
45 | /* There are additional complications because this file may be compiled |
46 | without VFP support enabled, and we also can't assume that the |
47 | assembler has VFP instructions enabled. To get around this we use the |
48 | generic coprocessor mnemonics and avoid asking GCC to put float values |
49 | in VFP registers. */ |
50 | |
51 | /* First: invalid exception. */ |
52 | if (FE_INVALID & excepts) |
53 | __asm__ __volatile__ ( |
54 | "ldc p10, cr0, %1\n\t" /* flds s0, %1 */ |
55 | "cdp p10, 8, cr0, cr0, cr0, 0\n\t" /* fdivs s0, s0, s0 */ |
56 | "mrc p10, 7, %0, cr1, cr0, 0" : "=r" (fpscr) /* fmrx %0, fpscr */ |
57 | : "m" (fp_zero) |
58 | : "s0" ); |
59 | |
60 | /* Next: division by zero. */ |
61 | if (FE_DIVBYZERO & excepts) |
62 | __asm__ __volatile__ ( |
63 | "ldc p10, cr0, %1\n\t" /* flds s0, %1 */ |
64 | "ldcl p10, cr0, %2\n\t" /* flds s1, %2 */ |
65 | "cdp p10, 8, cr0, cr0, cr0, 1\n\t" /* fdivs s0, s0, s1 */ |
66 | "mrc p10, 7, %0, cr1, cr0, 0" : "=r" (fpscr) /* fmrx %0, fpscr */ |
67 | : "m" (fp_one), "m" (fp_zero) |
68 | : "s0" , "s1" ); |
69 | |
70 | /* Next: overflow. */ |
71 | if (FE_OVERFLOW & excepts) |
72 | /* There's no way to raise overflow without also raising inexact. */ |
73 | __asm__ __volatile__ ( |
74 | "ldc p10, cr0, %1\n\t" /* flds s0, %1 */ |
75 | "ldcl p10, cr0, %2\n\t" /* flds s1, %2 */ |
76 | "cdp p10, 3, cr0, cr0, cr0, 1\n\t" /* fadds s0, s0, s1 */ |
77 | "mrc p10, 7, %0, cr1, cr0, 0" : "=r" (fpscr) /* fmrx %0, fpscr */ |
78 | : "m" (fp_max), "m" (fp_1e32) |
79 | : "s0" , "s1" ); |
80 | |
81 | /* Next: underflow. */ |
82 | if (FE_UNDERFLOW & excepts) |
83 | __asm__ __volatile__ ( |
84 | "ldc p10, cr0, %1\n\t" /* flds s0, %1 */ |
85 | "ldcl p10, cr0, %2\n\t" /* flds s1, %2 */ |
86 | "cdp p10, 8, cr0, cr0, cr0, 1\n\t" /* fdivs s0, s0, s1 */ |
87 | "mrc p10, 7, %0, cr1, cr0, 0" : "=r" (fpscr) /* fmrx %0, fpscr */ |
88 | : "m" (fp_min), "m" (fp_three) |
89 | : "s0" , "s1" ); |
90 | |
91 | /* Last: inexact. */ |
92 | if (FE_INEXACT & excepts) |
93 | __asm__ __volatile__ ( |
94 | "ldc p10, cr0, %1\n\t" /* flds s0, %1 */ |
95 | "ldcl p10, cr0, %2\n\t" /* flds s1, %2 */ |
96 | "cdp p10, 8, cr0, cr0, cr0, 1\n\t" /* fdivs s0, s0, s1 */ |
97 | "mrc p10, 7, %0, cr1, cr0, 0" : "=r" (fpscr) /* fmrx %0, fpscr */ |
98 | : "m" (fp_two), "m" (fp_three) |
99 | : "s0" , "s1" ); |
100 | |
101 | /* Success. */ |
102 | return 0; |
103 | } |
104 | } |
105 | libm_hidden_def (__feraiseexcept) |
106 | weak_alias (__feraiseexcept, feraiseexcept) |
107 | libm_hidden_weak (feraiseexcept) |
108 | |