arm_cpudetect.c revision 1b362b15af34006e6a11974088a46d42b903418e 
1/*
2 *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
3 *
4 *  Use of this source code is governed by a BSD-style license
5 *  that can be found in the LICENSE file in the root of the source
6 *  tree. An additional intellectual property rights grant can be found
7 *  in the file PATENTS.  All contributing project authors may
8 *  be found in the AUTHORS file in the root of the source tree.
9 */
10
11#include <stdlib.h>
12#include <string.h>
13#include "arm.h"
14
15static int arm_cpu_env_flags(int *flags)
16{
17    char *env;
18    env = getenv("VPX_SIMD_CAPS");
19    if (env && *env)
20    {
21        *flags = (int)strtol(env, NULL, 0);
22        return 0;
23    }
24    *flags = 0;
25    return -1;
26}
27
28static int arm_cpu_env_mask(void)
29{
30    char *env;
31    env = getenv("VPX_SIMD_CAPS_MASK");
32    return env && *env ? (int)strtol(env, NULL, 0) : ~0;
33}
34
35#if !CONFIG_RUNTIME_CPU_DETECT
36
37int arm_cpu_caps(void)
38{
39  /* This function should actually be a no-op. There is no way to adjust any of
40   * these because the RTCD tables do not exist: the functions are called
41   * statically */
42    int flags;
43    int mask;
44    if (!arm_cpu_env_flags(&flags))
45    {
46        return flags;
47    }
48    mask = arm_cpu_env_mask();
49#if HAVE_EDSP
50    flags |= HAS_EDSP;
51#endif /* HAVE_EDSP */
52#if HAVE_MEDIA
53    flags |= HAS_MEDIA;
54#endif /* HAVE_MEDIA */
55#if HAVE_NEON
56    flags |= HAS_NEON;
57#endif /* HAVE_NEON */
58    return flags & mask;
59}
60
61#elif defined(_MSC_VER) /* end !CONFIG_RUNTIME_CPU_DETECT */
62/*For GetExceptionCode() and EXCEPTION_ILLEGAL_INSTRUCTION.*/
63#define WIN32_LEAN_AND_MEAN
64#define WIN32_EXTRA_LEAN
65#include <windows.h>
66
67int arm_cpu_caps(void)
68{
69    int flags;
70    int mask;
71    if (!arm_cpu_env_flags(&flags))
72    {
73        return flags;
74    }
75    mask = arm_cpu_env_mask();
76    /* MSVC has no inline __asm support for ARM, but it does let you __emit
77     *  instructions via their assembled hex code.
78     * All of these instructions should be essentially nops.
79     */
80#if HAVE_EDSP
81    if (mask & HAS_EDSP)
82    {
83        __try
84        {
85            /*PLD [r13]*/
86            __emit(0xF5DDF000);
87            flags |= HAS_EDSP;
88        }
89        __except(GetExceptionCode() == EXCEPTION_ILLEGAL_INSTRUCTION)
90        {
91            /*Ignore exception.*/
92        }
93    }
94#if HAVE_MEDIA
95    if (mask & HAS_MEDIA)
96        __try
97        {
98            /*SHADD8 r3,r3,r3*/
99            __emit(0xE6333F93);
100            flags |= HAS_MEDIA;
101        }
102        __except(GetExceptionCode() == EXCEPTION_ILLEGAL_INSTRUCTION)
103        {
104            /*Ignore exception.*/
105        }
106    }
107#if HAVE_NEON
108    if (mask & HAS_NEON)
109    {
110        __try
111        {
112            /*VORR q0,q0,q0*/
113            __emit(0xF2200150);
114            flags |= HAS_NEON;
115        }
116        __except(GetExceptionCode() == EXCEPTION_ILLEGAL_INSTRUCTION)
117        {
118            /*Ignore exception.*/
119        }
120    }
121#endif /* HAVE_NEON */
122#endif /* HAVE_MEDIA */
123#endif /* HAVE_EDSP */
124    return flags & mask;
125}
126
127#elif defined(__ANDROID__) /* end _MSC_VER */
128#include <cpu-features.h>
129
130int arm_cpu_caps(void)
131{
132    int flags;
133    int mask;
134    uint64_t features;
135    if (!arm_cpu_env_flags(&flags))
136    {
137        return flags;
138    }
139    mask = arm_cpu_env_mask();
140    features = android_getCpuFeatures();
141
142#if HAVE_EDSP
143    flags |= HAS_EDSP;
144#endif /* HAVE_EDSP */
145#if HAVE_MEDIA
146    flags |= HAS_MEDIA;
147#endif /* HAVE_MEDIA */
148#if HAVE_NEON
149    if (features & ANDROID_CPU_ARM_FEATURE_NEON)
150        flags |= HAS_NEON;
151#endif /* HAVE_NEON */
152    return flags & mask;
153}
154
155#elif defined(__linux__) /* end __ANDROID__ */
156#include <stdio.h>
157
158int arm_cpu_caps(void)
159{
160    FILE *fin;
161    int flags;
162    int mask;
163    if (!arm_cpu_env_flags(&flags))
164    {
165        return flags;
166    }
167    mask = arm_cpu_env_mask();
168    /* Reading /proc/self/auxv would be easier, but that doesn't work reliably
169     *  on Android.
170     * This also means that detection will fail in Scratchbox.
171     */
172    fin = fopen("/proc/cpuinfo","r");
173    if(fin != NULL)
174    {
175        /* 512 should be enough for anybody (it's even enough for all the flags
176         * that x86 has accumulated... so far).
177         */
178        char buf[512];
179        while (fgets(buf, 511, fin) != NULL)
180        {
181#if HAVE_EDSP || HAVE_NEON
182            if (memcmp(buf, "Features", 8) == 0)
183            {
184                char *p;
185#if HAVE_EDSP
186                p=strstr(buf, " edsp");
187                if (p != NULL && (p[5] == ' ' || p[5] == '\n'))
188                {
189                    flags |= HAS_EDSP;
190                }
191#if HAVE_NEON
192                p = strstr(buf, " neon");
193                if (p != NULL && (p[5] == ' ' || p[5] == '\n'))
194                {
195                    flags |= HAS_NEON;
196                }
197#endif /* HAVE_NEON */
198#endif /* HAVE_EDSP */
199            }
200#endif /* HAVE_EDSP || HAVE_NEON */
201#if HAVE_MEDIA
202            if (memcmp(buf, "CPU architecture:",17) == 0){
203                int version;
204                version = atoi(buf+17);
205                if (version >= 6)
206                {
207                    flags |= HAS_MEDIA;
208                }
209            }
210#endif /* HAVE_MEDIA */
211        }
212        fclose(fin);
213    }
214    return flags & mask;
215}
216#else /* end __linux__ */
217#error "--enable-runtime-cpu-detect selected, but no CPU detection method " \
218 "available for your platform. Reconfigure with --disable-runtime-cpu-detect."
219#endif
220