Mercurial > hg > CbC > CbC_gcc
comparison gcc/config/i386/crtfastmath.c @ 0:a06113de4d67
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author | kent <kent@cr.ie.u-ryukyu.ac.jp> |
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date | Fri, 17 Jul 2009 14:47:48 +0900 |
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-1:000000000000 | 0:a06113de4d67 |
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1 /* | |
2 * Copyright (C) 2005, 2007, 2009 Free Software Foundation, Inc. | |
3 * | |
4 * This file is free software; you can redistribute it and/or modify it | |
5 * under the terms of the GNU General Public License as published by the | |
6 * Free Software Foundation; either version 3, or (at your option) any | |
7 * later version. | |
8 * | |
9 * This file is distributed in the hope that it will be useful, but | |
10 * WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 * General Public License for more details. | |
13 * | |
14 * Under Section 7 of GPL version 3, you are granted additional | |
15 * permissions described in the GCC Runtime Library Exception, version | |
16 * 3.1, as published by the Free Software Foundation. | |
17 * | |
18 * You should have received a copy of the GNU General Public License and | |
19 * a copy of the GCC Runtime Library Exception along with this program; | |
20 * see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
21 * <http://www.gnu.org/licenses/>. | |
22 */ | |
23 | |
24 #define MXCSR_DAZ (1 << 6) /* Enable denormals are zero mode */ | |
25 #define MXCSR_FTZ (1 << 15) /* Enable flush to zero mode */ | |
26 | |
27 #ifndef __x86_64__ | |
28 /* All 64-bit targets have SSE and DAZ; | |
29 only check them explicitly for 32-bit ones. */ | |
30 #include "cpuid.h" | |
31 #endif | |
32 | |
33 static void __attribute__((constructor)) | |
34 #ifndef __x86_64__ | |
35 /* The i386 ABI only requires 4-byte stack alignment, so this is necessary | |
36 to make sure the fxsave struct gets correct alignment. | |
37 See PR27537 and PR28621. */ | |
38 __attribute__ ((force_align_arg_pointer)) | |
39 #endif | |
40 set_fast_math (void) | |
41 { | |
42 #ifndef __x86_64__ | |
43 unsigned int eax, ebx, ecx, edx; | |
44 | |
45 if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx)) | |
46 return; | |
47 | |
48 if (edx & bit_SSE) | |
49 { | |
50 unsigned int mxcsr = __builtin_ia32_stmxcsr (); | |
51 | |
52 mxcsr |= MXCSR_FTZ; | |
53 | |
54 if (edx & bit_FXSAVE) | |
55 { | |
56 /* Check if DAZ is available. */ | |
57 struct | |
58 { | |
59 unsigned short int cwd; | |
60 unsigned short int swd; | |
61 unsigned short int twd; | |
62 unsigned short int fop; | |
63 long int fip; | |
64 long int fcs; | |
65 long int foo; | |
66 long int fos; | |
67 long int mxcsr; | |
68 long int mxcsr_mask; | |
69 long int st_space[32]; | |
70 long int xmm_space[32]; | |
71 long int padding[56]; | |
72 } __attribute__ ((aligned (16))) fxsave; | |
73 | |
74 __builtin_memset (&fxsave, 0, sizeof (fxsave)); | |
75 | |
76 asm volatile ("fxsave %0" : "=m" (fxsave) : "m" (fxsave)); | |
77 | |
78 if (fxsave.mxcsr_mask & MXCSR_DAZ) | |
79 mxcsr |= MXCSR_DAZ; | |
80 } | |
81 | |
82 __builtin_ia32_ldmxcsr (mxcsr); | |
83 } | |
84 #else | |
85 unsigned int mxcsr = __builtin_ia32_stmxcsr (); | |
86 mxcsr |= MXCSR_DAZ | MXCSR_FTZ; | |
87 __builtin_ia32_ldmxcsr (mxcsr); | |
88 #endif | |
89 } |