aom_ports/arm_cpudetect.c

   1 /*
   2  * Copyright (c) 2016, Alliance for Open Media. All rights reserved
   3  *
   4  * This source code is subject to the terms of the BSD 2 Clause License and
   5  * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
   6  * was not distributed with this source code in the LICENSE file, you can
   7  * obtain it at www.aomedia.org/license/software. If the Alliance for Open
   8  * Media Patent License 1.0 was not distributed with this source code in the
   9  * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
  10  */
  11
  12 #include <stdlib.h>
  13 #include <string.h>
  14 #include "aom_ports/arm.h"
  15 #include "config/aom_config.h"
  16
  17 #ifdef WINAPI_FAMILY
  18 #include <winapifamily.h>
  19 #if !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
  20 #define getenv(x) NULL
  21 #endif
  22 #endif
  23
  24 static int arm_cpu_env_flags(int *flags) {
  25   char *env;
  26   env = getenv("AOM_SIMD_CAPS");
  27   if (env && *env) {
  28     *flags = (int)strtol(env, NULL, 0);
  29     return 0;
  30   }
  31   *flags = 0;
  32   return -1;
  33 }
  34
  35 static int arm_cpu_env_mask(void) {
  36   char *env;
  37   env = getenv("AOM_SIMD_CAPS_MASK");
  38   return env && *env ? (int)strtol(env, NULL, 0) : ~0;
  39 }
  40
  41 #if !CONFIG_RUNTIME_CPU_DETECT || defined(__APPLE__)
  42
  43 int aom_arm_cpu_caps(void) {
  44   /* This function should actually be a no-op. There is no way to adjust any of
  45    * these because the RTCD tables do not exist: the functions are called
  46    * statically */
  47   int flags;
  48   int mask;
  49   if (!arm_cpu_env_flags(&flags)) {
  50     return flags;
  51   }
  52   mask = arm_cpu_env_mask();
  53 #if HAVE_NEON
  54   flags |= HAS_NEON;
  55 #endif /* HAVE_NEON */
  56   return flags & mask;
  57 }
  58
  59 #elif defined(_MSC_VER) /* end !CONFIG_RUNTIME_CPU_DETECT || __APPLE__ */
  60 /*For GetExceptionCode() and EXCEPTION_ILLEGAL_INSTRUCTION.*/
  61 #define WIN32_LEAN_AND_MEAN
  62 #define WIN32_EXTRA_LEAN
  63 #include <windows.h>
  64
  65 int aom_arm_cpu_caps(void) {
  66   int flags;
  67   int mask;
  68   if (!arm_cpu_env_flags(&flags)) {
  69     return flags;
  70   }
  71   mask = arm_cpu_env_mask();
  72 /* MSVC has no inline __asm support for ARM, but it does let you __emit
  73  *  instructions via their assembled hex code.
  74  * All of these instructions should be essentially nops.
  75  */
  76 #if HAVE_NEON
  77   if (mask & HAS_NEON) {
  78     __try {
  79       /*VORR q0,q0,q0*/
  80       __emit(0xF2200150);
  81       flags |= HAS_NEON;
  82     } __except (GetExceptionCode() == EXCEPTION_ILLEGAL_INSTRUCTION) {
  83       /*Ignore exception.*/
  84     }
  85   }
  86 #endif /* HAVE_NEON */
  87   return flags & mask;
  88 }
  89
  90 #elif defined(__ANDROID__) /* end _MSC_VER */
  91 #include <cpu-features.h>
  92
  93 int aom_arm_cpu_caps(void) {
  94   int flags;
  95   int mask;
  96   uint64_t features;
  97   if (!arm_cpu_env_flags(&flags)) {
  98     return flags;
  99   }
 100   mask = arm_cpu_env_mask();
 101   features = android_getCpuFeatures();
 102
 103 #if HAVE_NEON
 104   if (features & ANDROID_CPU_ARM_FEATURE_NEON) flags |= HAS_NEON;
 105 #endif /* HAVE_NEON */
 106   return flags & mask;
 107 }
 108
 109 #elif defined(__linux__) /* end __ANDROID__ */
 110
 111 #include <stdio.h>
 112
 113 int aom_arm_cpu_caps(void) {
 114   FILE *fin;
 115   int flags;
 116   int mask;
 117   if (!arm_cpu_env_flags(&flags)) {
 118     return flags;
 119   }
 120   mask = arm_cpu_env_mask();
 121   /* Reading /proc/self/auxv would be easier, but that doesn't work reliably
 122    *  on Android.
 123    * This also means that detection will fail in Scratchbox.
 124    */
 125   fin = fopen("/proc/cpuinfo", "r");
 126   if (fin != NULL) {
 127     /* 512 should be enough for anybody (it's even enough for all the flags
 128      * that x86 has accumulated... so far).
 129      */
 130     char buf[512];
 131     while (fgets(buf, 511, fin) != NULL) {
 132 #if HAVE_NEON
 133       if (memcmp(buf, "Features", 8) == 0) {
 134         char *p;
 135         p = strstr(buf, " neon");
 136         if (p != NULL && (p[5] == ' ' || p[5] == '\n')) {
 137           flags |= HAS_NEON;
 138         }
 139       }
 140 #endif /* HAVE_NEON */
 141     }
 142     fclose(fin);
 143   }
 144   return flags & mask;
 145 }
 146 #else  /* end __linux__ */
 147 #error \
 148     "Runtime CPU detection selected, but no CPU detection method " \
 149 "available for your platform. Rerun cmake with -DCONFIG_RUNTIME_CPU_DETECT=0."
 150 #endif