text: /*
   * This file is part of FFmpeg.
   *
   * FFmpeg 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.
   *
   * FFmpeg 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 FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #include "../cpu.h"
  #include "../cpu_internal.h"
  
  // TODO: those macros need defined by makefile.
  #define HAVE_ARMV5TE_EXTERNAL 	0
  #define HAVE_ARMV5TE_INLINE 	0
  #define HAVE_ARMV6_EXTERNAL 	0
  #define HAVE_ARMV6_INLINE 		0
  #define HAVE_ARMV6T2_EXTERNAL	0
  #define HAVE_ARMV6T2_INLINE		0
  #define HAVE_VFP_EXTERNAL		0
  #define HAVE_VFP_INLINE			0
  #define HAVE_VFPV3_EXTERNAL		0
  #define HAVE_VFPV3_INLINE		0
  #define HAVE_NEON_EXTERNAL		1
  #define HAVE_NEON_INLINE		1
  
  #define HAVE_ARMV5TE			0
  #define HAVE_ARMV6				0
  #define HAVE_ARMV6T2			0
  #define HAVE_VFP				0
  #define HAVE_VFPV3				0
  
  #define CORE_FLAG(f) \
      (AV_CPU_FLAG_ ## f * (HAVE_ ## f ## _EXTERNAL || HAVE_ ## f ## _INLINE))
  
  #define CORE_CPU_FLAGS                          \
      (CORE_FLAG(ARMV5TE) |                       \
       CORE_FLAG(ARMV6)   |                       \
       CORE_FLAG(ARMV6T2) |                       \
       CORE_FLAG(VFP)     |                       \
       CORE_FLAG(VFPV3)   |                       \
       CORE_FLAG(NEON))
  
  #if defined __linux__ || defined __ANDROID__
  
  #include <stdint.h>
  #include <stdio.h>
  #include <string.h>
  
  #define AT_HWCAP        16
  
  /* Relevant HWCAP values from kernel headers */
  #define HWCAP_VFP       (1 << 6)
  #define HWCAP_EDSP      (1 << 7)
  #define HWCAP_THUMBEE   (1 << 11)
  #define HWCAP_NEON      (1 << 12)
  #define HWCAP_VFPv3     (1 << 13)
  #define HWCAP_TLS       (1 << 15)
  
  static int av_strstart(const char *str, const char *pfx, const char **ptr)
  {
      while (*pfx && *pfx == *str) {
          pfx++;
          str++;
      }
      if (!*pfx && ptr)
          *ptr = str;
      return !*pfx;
  }
  
  static int get_hwcap(uint32_t *hwcap)
  {
      struct { uint32_t a_type; uint32_t a_val; } auxv;
      FILE *f = fopen("/proc/self/auxv", "r");
      int err = -1;
  
      if (!f)
          return -1;
  
      while (fread(&auxv, sizeof(auxv), 1, f) > 0) {
          if (auxv.a_type == AT_HWCAP) {
              *hwcap = auxv.a_val;
              err = 0;
              break;
          }
      }
  
      fclose(f);
      return err;
  }
  
  static int get_cpuinfo(uint32_t *hwcap)
  {
      FILE *f = fopen("/proc/cpuinfo", "r");
      char buf[200];
  
      if (!f)
          return -1;
  
      *hwcap = 0;
      while (fgets(buf, sizeof(buf), f)) {
          if (av_strstart(buf, "Features", NULL)) {
              if (strstr(buf, " edsp "))
                  *hwcap |= HWCAP_EDSP;
              if (strstr(buf, " tls "))
                  *hwcap |= HWCAP_TLS;
              if (strstr(buf, " thumbee "))
                  *hwcap |= HWCAP_THUMBEE;
              if (strstr(buf, " vfp "))
                  *hwcap |= HWCAP_VFP;
              if (strstr(buf, " vfpv3 "))
                  *hwcap |= HWCAP_VFPv3;
              if (strstr(buf, " neon ") || strstr(buf, " asimd "))
                  *hwcap |= HWCAP_NEON;
              if (strstr(buf, " fp ")) // Listed on 64 bit ARMv8 kernels
                  *hwcap |= HWCAP_VFP | HWCAP_VFPv3;
              break;
          }
      }
      fclose(f);
      return 0;
  }
  
  int ff_get_cpu_flags_arm(void)
  {
      int flags = CORE_CPU_FLAGS;
      uint32_t hwcap;
  
      if (get_hwcap(&hwcap) < 0)
          if (get_cpuinfo(&hwcap) < 0)
              return flags;
  
  #define check_cap(cap, flag) do {               \
          if (hwcap & HWCAP_ ## cap)              \
              flags |= AV_CPU_FLAG_ ## flag;      \
      } while (0)
  
      /* No flags explicitly indicate v6 or v6T2 so check others which
         imply support. */
      check_cap(EDSP,    ARMV5TE);
      check_cap(TLS,     ARMV6);
      check_cap(THUMBEE, ARMV6T2);
      check_cap(VFP,     VFP);
      check_cap(VFPv3,   VFPV3);
      check_cap(NEON,    NEON);
  
      /* The v6 checks above are not reliable so let higher flags
         trickle down. */
      if (flags & (AV_CPU_FLAG_VFPV3 | AV_CPU_FLAG_NEON))
          flags |= AV_CPU_FLAG_ARMV6T2;
      else if (flags & (AV_CPU_FLAG_ARMV6T2 | AV_CPU_FLAG_ARMV6))
      /* Some functions use the 'setend' instruction which is deprecated on ARMv8
       * and serializing on some ARMv7 cores. This ensures such functions
       * are only enabled on ARMv6. */
          flags |= AV_CPU_FLAG_SETEND;
  
      if (flags & AV_CPU_FLAG_ARMV6T2)
          flags |= AV_CPU_FLAG_ARMV6;
  
      /* set the virtual VFPv2 vector mode flag */
      if ((flags & AV_CPU_FLAG_VFP) && !(flags & (AV_CPU_FLAG_VFPV3 | AV_CPU_FLAG_NEON)))
          flags |= AV_CPU_FLAG_VFP_VM;
  
      return flags;
  }
  
  #else
  
  int ff_get_cpu_flags_arm(void)
  {
      return AV_CPU_FLAG_ARMV5TE * HAVE_ARMV5TE |
             AV_CPU_FLAG_ARMV6   * HAVE_ARMV6   |
             AV_CPU_FLAG_ARMV6T2 * HAVE_ARMV6T2 |
             AV_CPU_FLAG_VFP     * HAVE_VFP     |
             AV_CPU_FLAG_VFPV3   * HAVE_VFPV3   |
             AV_CPU_FLAG_NEON    * HAVE_NEON    |
             AV_CPU_FLAG_SETEND  * !(HAVE_NEON | HAVE_VFPV3);
  }
  
  #endif
  
  size_t ff_get_cpu_max_align_arm(void)
  {
      int flags = av_get_cpu_flags();
  
      if (flags & AV_CPU_FLAG_NEON)
          return 16;
  
      return 8;
  }
  