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