1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
|
/* Initialize CPU feature data.
This file is part of the GNU C Library.
Copyright (C) 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
Contributed by Ulrich Drepper <drepper@redhat.com>.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <atomic.h>
#include <cpuid.h>
#include "init-arch.h"
struct cpu_features __cpu_features attribute_hidden;
static void
get_common_indeces (unsigned int *family, unsigned int *model)
{
__cpuid (1, __cpu_features.cpuid[COMMON_CPUID_INDEX_1].eax,
__cpu_features.cpuid[COMMON_CPUID_INDEX_1].ebx,
__cpu_features.cpuid[COMMON_CPUID_INDEX_1].ecx,
__cpu_features.cpuid[COMMON_CPUID_INDEX_1].edx);
unsigned int eax = __cpu_features.cpuid[COMMON_CPUID_INDEX_1].eax;
*family = (eax >> 8) & 0x0f;
*model = (eax >> 4) & 0x0f;
}
void
__init_cpu_features (void)
{
unsigned int ebx;
unsigned int ecx;
unsigned int edx;
unsigned int family = 0;
unsigned int model = 0;
enum cpu_features_kind kind;
__cpuid (0, __cpu_features.max_cpuid, ebx, ecx, edx);
/* This spells out "GenuineIntel". */
if (ebx == 0x756e6547 && ecx == 0x6c65746e && edx == 0x49656e69)
{
kind = arch_kind_intel;
get_common_indeces (&family, &model);
/* Intel processors prefer SSE instruction for memory/string
routines if they are available. */
__cpu_features.feature[index_Prefer_SSE_for_memop]
|= bit_Prefer_SSE_for_memop;
unsigned int eax = __cpu_features.cpuid[COMMON_CPUID_INDEX_1].eax;
unsigned int extended_family = (eax >> 20) & 0xff;
unsigned int extended_model = (eax >> 12) & 0xf0;
if (family == 0x0f)
{
family += extended_family;
model += extended_model;
}
else if (family == 0x06)
{
ecx = __cpu_features.cpuid[COMMON_CPUID_INDEX_1].ecx;
model += extended_model;
switch (model)
{
case 0x1c:
case 0x26:
/* BSF is slow on Atom. */
__cpu_features.feature[index_Slow_BSF] |= bit_Slow_BSF;
break;
default:
/* Unknown family 0x06 processors. Assuming this is one
of Core i3/i5/i7 processors if AVX is available. */
if ((ecx & bit_AVX) == 0)
break;
case 0x1a:
case 0x1e:
case 0x1f:
case 0x25:
case 0x2c:
case 0x2e:
case 0x2f:
/* Rep string instructions, copy backward and unaligned loads
are fast on Intel Core i3, i5 and i7. */
#if index_Fast_Rep_String != index_Fast_Copy_Backward
# error index_Fast_Rep_String != index_Fast_Copy_Backward
#endif
#if index_Fast_Rep_String != index_Fast_Unaligned_Load
# error index_Fast_Rep_String != index_Fast_Unaligned_Load
#endif
__cpu_features.feature[index_Fast_Rep_String]
|= (bit_Fast_Rep_String
| bit_Fast_Copy_Backward
| bit_Fast_Unaligned_Load);
break;
}
}
}
/* This spells out "AuthenticAMD". */
else if (ebx == 0x68747541 && ecx == 0x444d4163 && edx == 0x69746e65)
{
kind = arch_kind_amd;
get_common_indeces (&family, &model);
unsigned int ecx = __cpu_features.cpuid[COMMON_CPUID_INDEX_1].ecx;
/* AMD processors prefer SSE instructions for memory/string routines
if they are available, otherwise they prefer integer instructions. */
if ((ecx & 0x200))
__cpu_features.feature[index_Prefer_SSE_for_memop]
|= bit_Prefer_SSE_for_memop;
}
else
kind = arch_kind_other;
__cpu_features.family = family;
__cpu_features.model = model;
atomic_write_barrier ();
__cpu_features.kind = kind;
}
#undef __get_cpu_features
const struct cpu_features *
__get_cpu_features (void)
{
if (__cpu_features.kind == arch_kind_unknown)
__init_cpu_features ();
return &__cpu_features;
}
|