michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: /* compile-time and runtime tests for whether to use various ARM extensions */
michael@0: 
michael@0: #include "mozilla/NullPtr.h"
michael@0: 
michael@0: #include "arm.h"
michael@0: 
michael@0: #if defined(MOZILLA_ARM_HAVE_CPUID_DETECTION)
michael@0: namespace {
michael@0: 
michael@0: // arm.h has parallel #ifs which declare MOZILLA_ARM_HAVE_CPUID_DETECTION.
michael@0: // We don't check it here so that we get compile errors if it's defined, but
michael@0: // we don't compile one of these detection methods. The detection code here is
michael@0: // based on the CPU detection in libtheora.
michael@0: 
michael@0: #  if defined(_MSC_VER)
michael@0: //For GetExceptionCode() and EXCEPTION_ILLEGAL_INSTRUCTION.
michael@0: #    define WIN32_LEAN_AND_MEAN
michael@0: #    define WIN32_EXTRA_LEAN
michael@0: #    include <windows.h>
michael@0: 
michael@0: #    if !defined(MOZILLA_PRESUME_EDSP)
michael@0: static bool
michael@0: check_edsp(void)
michael@0: {
michael@0: #      if defined(MOZILLA_MAY_SUPPORT_EDSP)
michael@0:   __try
michael@0:   {
michael@0:     //PLD [r13]
michael@0:     __emit(0xF5DDF000);
michael@0:     return true;
michael@0:   }
michael@0:   __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION)
michael@0:   {
michael@0:     //Ignore exception.
michael@0:   }
michael@0: #      endif
michael@0:   return false;
michael@0: }
michael@0: #    endif // !MOZILLA_PRESUME_EDSP
michael@0: 
michael@0: #    if !defined(MOZILLA_PRESUME_ARMV6)
michael@0: static bool
michael@0: check_armv6(void)
michael@0: {
michael@0: #      if defined(MOZILLA_MAY_SUPPORT_ARMV6)
michael@0:   __try
michael@0:   {
michael@0:     //SHADD8 r3,r3,r3
michael@0:     __emit(0xE6333F93);
michael@0:     return true;
michael@0:   }
michael@0:   __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION)
michael@0:   {
michael@0:     //Ignore exception.
michael@0:   }
michael@0: #      endif
michael@0:   return false;
michael@0: }
michael@0: #    endif // !MOZILLA_PRESUME_ARMV6
michael@0: 
michael@0: #    if !defined(MOZILLA_PRESUME_ARMV7)
michael@0: static bool
michael@0: check_armv7(void)
michael@0: {
michael@0: #      if defined(MOZILLA_MAY_SUPPORT_ARMV7)
michael@0:   __try
michael@0:   {
michael@0:     // ARMv7 DMB (Data Memory Barrier) for stores (DMB.ST)
michael@0:     // The Data Memory Barrier existed before ARMv7 as a
michael@0:     // cp15 operation, but ARMv7 introduced a dedicated
michael@0:     // instruction, DMB.
michael@0:     emit(0xF57FF05E);
michael@0:     return true;
michael@0:   }
michael@0:   __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION)
michael@0:   {
michael@0:     //Ignore exception.
michael@0:   }
michael@0: #      endif
michael@0:   return false;
michael@0: }
michael@0: #    endif // !MOZILLA_PRESUME_ARMV7
michael@0: 
michael@0: #    if !defined(MOZILLA_PRESUME_NEON)
michael@0: static bool
michael@0: check_neon(void)
michael@0: {
michael@0: #      if defined(MOZILLA_MAY_SUPPORT_NEON)
michael@0:   __try
michael@0:   {
michael@0:     //VORR q0,q0,q0
michael@0:     __emit(0xF2200150);
michael@0:     return true;
michael@0:   }
michael@0:   __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION)
michael@0:   {
michael@0:     //Ignore exception.
michael@0:   }
michael@0: #      endif
michael@0:   return false;
michael@0: }
michael@0: #    endif // !MOZILLA_PRESUME_NEON
michael@0: 
michael@0: #  elif defined(__linux__) || defined(ANDROID)
michael@0: #    include <stdio.h>
michael@0: #    include <stdlib.h>
michael@0: #    include <string.h>
michael@0: 
michael@0: enum{
michael@0:   MOZILLA_HAS_EDSP_FLAG=1,
michael@0:   MOZILLA_HAS_ARMV6_FLAG=2,
michael@0:   MOZILLA_HAS_ARMV7_FLAG=4,
michael@0:   MOZILLA_HAS_NEON_FLAG=8
michael@0: };
michael@0: 
michael@0: static unsigned
michael@0: get_arm_cpu_flags(void)
michael@0: {
michael@0:   unsigned  flags;
michael@0:   FILE     *fin;
michael@0:   bool      armv6_processor = false;
michael@0:   flags = 0;
michael@0:   /*Reading /proc/self/auxv would be easier, but that doesn't work reliably on
michael@0:     Android. This also means that detection will fail in Scratchbox, which is
michael@0:     desirable, as NEON does not work in the qemu shipped with the Maemo 5 SDK.
michael@0:     I don't know if /proc/self/auxv would do any better in that case, anyway,
michael@0:     or if it would return random flags from the host CPU.*/
michael@0:   fin = fopen ("/proc/cpuinfo","r");
michael@0:   if (fin != nullptr)
michael@0:   {
michael@0:     /*512 should be enough for anybody (it's even enough for all the flags that
michael@0:       x86 has accumulated... so far).*/
michael@0:     char buf[512];
michael@0:     while (fgets(buf, 511, fin) != nullptr)
michael@0:     {
michael@0:       if (memcmp(buf, "Features", 8) == 0)
michael@0:       {
michael@0:         char *p;
michael@0:         p = strstr(buf, " edsp");
michael@0:         if (p != nullptr && (p[5] == ' ' || p[5] == '\n'))
michael@0:           flags |= MOZILLA_HAS_EDSP_FLAG;
michael@0:         p = strstr(buf, " neon");
michael@0:         if( p != nullptr && (p[5] == ' ' || p[5] == '\n'))
michael@0:           flags |= MOZILLA_HAS_NEON_FLAG;
michael@0:       }
michael@0:       if (memcmp(buf, "CPU architecture:", 17) == 0)
michael@0:       {
michael@0:         int version;
michael@0:         version = atoi(buf + 17);
michael@0:         if (version >= 6)
michael@0:           flags |= MOZILLA_HAS_ARMV6_FLAG;
michael@0:         if (version >= 7)
michael@0:           flags |= MOZILLA_HAS_ARMV7_FLAG;
michael@0:       }
michael@0:       /* media/webrtc/trunk/src/system_wrappers/source/cpu_features_arm.c
michael@0:        * Unfortunately, it seems that certain ARMv6-based CPUs
michael@0:        * report an incorrect architecture number of 7!
michael@0:        *
michael@0:        * We try to correct this by looking at the 'elf_format'
michael@0:        * field reported by the 'Processor' field, which is of the
michael@0:        * form of "(v7l)" for an ARMv7-based CPU, and "(v6l)" for
michael@0:        * an ARMv6-one.
michael@0:        */
michael@0:       if (memcmp(buf, "Processor\t:", 11) == 0) {
michael@0:           if (strstr(buf, "(v6l)") != 0) {
michael@0:               armv6_processor = true;
michael@0:           }
michael@0:       }
michael@0:     }
michael@0:     fclose(fin);
michael@0:   }
michael@0:   if (armv6_processor) {
michael@0:       // ARMv6 pretending to be ARMv7? clear flag
michael@0:       if (flags & MOZILLA_HAS_ARMV7_FLAG) {
michael@0:           flags &= ~MOZILLA_HAS_ARMV7_FLAG;
michael@0:       }
michael@0:   }
michael@0:   return flags;
michael@0: }
michael@0: 
michael@0: // Cache a local copy so we only have to read /proc/cpuinfo once.
michael@0: static unsigned arm_cpu_flags = get_arm_cpu_flags();
michael@0: 
michael@0: #    if !defined(MOZILLA_PRESUME_EDSP)
michael@0: static bool
michael@0: check_edsp(void)
michael@0: {
michael@0:   return (arm_cpu_flags & MOZILLA_HAS_EDSP_FLAG) != 0;
michael@0: }
michael@0: #    endif
michael@0: 
michael@0: #    if !defined(MOZILLA_PRESUME_ARMV6)
michael@0: static bool
michael@0: check_armv6(void)
michael@0: {
michael@0:   return (arm_cpu_flags & MOZILLA_HAS_ARMV6_FLAG) != 0;
michael@0: }
michael@0: #    endif
michael@0: 
michael@0: #    if !defined(MOZILLA_PRESUME_ARMV7)
michael@0: static bool
michael@0: check_armv7(void)
michael@0: {
michael@0:   return (arm_cpu_flags & MOZILLA_HAS_ARMV7_FLAG) != 0;
michael@0: }
michael@0: #    endif
michael@0: 
michael@0: #    if !defined(MOZILLA_PRESUME_NEON)
michael@0: static bool
michael@0: check_neon(void)
michael@0: {
michael@0:   return (arm_cpu_flags & MOZILLA_HAS_NEON_FLAG) != 0;
michael@0: }
michael@0: #    endif
michael@0: 
michael@0: #  endif // defined(__linux__) || defined(ANDROID)
michael@0: 
michael@0: }
michael@0: 
michael@0: namespace mozilla {
michael@0:   namespace arm_private {
michael@0: #  if !defined(MOZILLA_PRESUME_EDSP)
michael@0:     bool edsp_enabled = check_edsp();
michael@0: #  endif
michael@0: #  if !defined(MOZILLA_PRESUME_ARMV6)
michael@0:     bool armv6_enabled = check_armv6();
michael@0: #  endif
michael@0: #  if !defined(MOZILLA_PRESUME_ARMV7)
michael@0:     bool armv7_enabled = check_armv7();
michael@0: #  endif
michael@0: #  if !defined(MOZILLA_PRESUME_NEON)
michael@0:     bool neon_enabled = check_neon();
michael@0: #  endif
michael@0:   } // namespace arm_private
michael@0: } // namespace mozilla
michael@0: 
michael@0: #endif // MOZILLA_ARM_HAVE_CPUID_DETECTION