1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/mozglue/build/arm.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,241 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +/* compile-time and runtime tests for whether to use various ARM extensions */
1.9 +
1.10 +#include "mozilla/NullPtr.h"
1.11 +
1.12 +#include "arm.h"
1.13 +
1.14 +#if defined(MOZILLA_ARM_HAVE_CPUID_DETECTION)
1.15 +namespace {
1.16 +
1.17 +// arm.h has parallel #ifs which declare MOZILLA_ARM_HAVE_CPUID_DETECTION.
1.18 +// We don't check it here so that we get compile errors if it's defined, but
1.19 +// we don't compile one of these detection methods. The detection code here is
1.20 +// based on the CPU detection in libtheora.
1.21 +
1.22 +# if defined(_MSC_VER)
1.23 +//For GetExceptionCode() and EXCEPTION_ILLEGAL_INSTRUCTION.
1.24 +# define WIN32_LEAN_AND_MEAN
1.25 +# define WIN32_EXTRA_LEAN
1.26 +# include <windows.h>
1.27 +
1.28 +# if !defined(MOZILLA_PRESUME_EDSP)
1.29 +static bool
1.30 +check_edsp(void)
1.31 +{
1.32 +# if defined(MOZILLA_MAY_SUPPORT_EDSP)
1.33 + __try
1.34 + {
1.35 + //PLD [r13]
1.36 + __emit(0xF5DDF000);
1.37 + return true;
1.38 + }
1.39 + __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION)
1.40 + {
1.41 + //Ignore exception.
1.42 + }
1.43 +# endif
1.44 + return false;
1.45 +}
1.46 +# endif // !MOZILLA_PRESUME_EDSP
1.47 +
1.48 +# if !defined(MOZILLA_PRESUME_ARMV6)
1.49 +static bool
1.50 +check_armv6(void)
1.51 +{
1.52 +# if defined(MOZILLA_MAY_SUPPORT_ARMV6)
1.53 + __try
1.54 + {
1.55 + //SHADD8 r3,r3,r3
1.56 + __emit(0xE6333F93);
1.57 + return true;
1.58 + }
1.59 + __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION)
1.60 + {
1.61 + //Ignore exception.
1.62 + }
1.63 +# endif
1.64 + return false;
1.65 +}
1.66 +# endif // !MOZILLA_PRESUME_ARMV6
1.67 +
1.68 +# if !defined(MOZILLA_PRESUME_ARMV7)
1.69 +static bool
1.70 +check_armv7(void)
1.71 +{
1.72 +# if defined(MOZILLA_MAY_SUPPORT_ARMV7)
1.73 + __try
1.74 + {
1.75 + // ARMv7 DMB (Data Memory Barrier) for stores (DMB.ST)
1.76 + // The Data Memory Barrier existed before ARMv7 as a
1.77 + // cp15 operation, but ARMv7 introduced a dedicated
1.78 + // instruction, DMB.
1.79 + emit(0xF57FF05E);
1.80 + return true;
1.81 + }
1.82 + __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION)
1.83 + {
1.84 + //Ignore exception.
1.85 + }
1.86 +# endif
1.87 + return false;
1.88 +}
1.89 +# endif // !MOZILLA_PRESUME_ARMV7
1.90 +
1.91 +# if !defined(MOZILLA_PRESUME_NEON)
1.92 +static bool
1.93 +check_neon(void)
1.94 +{
1.95 +# if defined(MOZILLA_MAY_SUPPORT_NEON)
1.96 + __try
1.97 + {
1.98 + //VORR q0,q0,q0
1.99 + __emit(0xF2200150);
1.100 + return true;
1.101 + }
1.102 + __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION)
1.103 + {
1.104 + //Ignore exception.
1.105 + }
1.106 +# endif
1.107 + return false;
1.108 +}
1.109 +# endif // !MOZILLA_PRESUME_NEON
1.110 +
1.111 +# elif defined(__linux__) || defined(ANDROID)
1.112 +# include <stdio.h>
1.113 +# include <stdlib.h>
1.114 +# include <string.h>
1.115 +
1.116 +enum{
1.117 + MOZILLA_HAS_EDSP_FLAG=1,
1.118 + MOZILLA_HAS_ARMV6_FLAG=2,
1.119 + MOZILLA_HAS_ARMV7_FLAG=4,
1.120 + MOZILLA_HAS_NEON_FLAG=8
1.121 +};
1.122 +
1.123 +static unsigned
1.124 +get_arm_cpu_flags(void)
1.125 +{
1.126 + unsigned flags;
1.127 + FILE *fin;
1.128 + bool armv6_processor = false;
1.129 + flags = 0;
1.130 + /*Reading /proc/self/auxv would be easier, but that doesn't work reliably on
1.131 + Android. This also means that detection will fail in Scratchbox, which is
1.132 + desirable, as NEON does not work in the qemu shipped with the Maemo 5 SDK.
1.133 + I don't know if /proc/self/auxv would do any better in that case, anyway,
1.134 + or if it would return random flags from the host CPU.*/
1.135 + fin = fopen ("/proc/cpuinfo","r");
1.136 + if (fin != nullptr)
1.137 + {
1.138 + /*512 should be enough for anybody (it's even enough for all the flags that
1.139 + x86 has accumulated... so far).*/
1.140 + char buf[512];
1.141 + while (fgets(buf, 511, fin) != nullptr)
1.142 + {
1.143 + if (memcmp(buf, "Features", 8) == 0)
1.144 + {
1.145 + char *p;
1.146 + p = strstr(buf, " edsp");
1.147 + if (p != nullptr && (p[5] == ' ' || p[5] == '\n'))
1.148 + flags |= MOZILLA_HAS_EDSP_FLAG;
1.149 + p = strstr(buf, " neon");
1.150 + if( p != nullptr && (p[5] == ' ' || p[5] == '\n'))
1.151 + flags |= MOZILLA_HAS_NEON_FLAG;
1.152 + }
1.153 + if (memcmp(buf, "CPU architecture:", 17) == 0)
1.154 + {
1.155 + int version;
1.156 + version = atoi(buf + 17);
1.157 + if (version >= 6)
1.158 + flags |= MOZILLA_HAS_ARMV6_FLAG;
1.159 + if (version >= 7)
1.160 + flags |= MOZILLA_HAS_ARMV7_FLAG;
1.161 + }
1.162 + /* media/webrtc/trunk/src/system_wrappers/source/cpu_features_arm.c
1.163 + * Unfortunately, it seems that certain ARMv6-based CPUs
1.164 + * report an incorrect architecture number of 7!
1.165 + *
1.166 + * We try to correct this by looking at the 'elf_format'
1.167 + * field reported by the 'Processor' field, which is of the
1.168 + * form of "(v7l)" for an ARMv7-based CPU, and "(v6l)" for
1.169 + * an ARMv6-one.
1.170 + */
1.171 + if (memcmp(buf, "Processor\t:", 11) == 0) {
1.172 + if (strstr(buf, "(v6l)") != 0) {
1.173 + armv6_processor = true;
1.174 + }
1.175 + }
1.176 + }
1.177 + fclose(fin);
1.178 + }
1.179 + if (armv6_processor) {
1.180 + // ARMv6 pretending to be ARMv7? clear flag
1.181 + if (flags & MOZILLA_HAS_ARMV7_FLAG) {
1.182 + flags &= ~MOZILLA_HAS_ARMV7_FLAG;
1.183 + }
1.184 + }
1.185 + return flags;
1.186 +}
1.187 +
1.188 +// Cache a local copy so we only have to read /proc/cpuinfo once.
1.189 +static unsigned arm_cpu_flags = get_arm_cpu_flags();
1.190 +
1.191 +# if !defined(MOZILLA_PRESUME_EDSP)
1.192 +static bool
1.193 +check_edsp(void)
1.194 +{
1.195 + return (arm_cpu_flags & MOZILLA_HAS_EDSP_FLAG) != 0;
1.196 +}
1.197 +# endif
1.198 +
1.199 +# if !defined(MOZILLA_PRESUME_ARMV6)
1.200 +static bool
1.201 +check_armv6(void)
1.202 +{
1.203 + return (arm_cpu_flags & MOZILLA_HAS_ARMV6_FLAG) != 0;
1.204 +}
1.205 +# endif
1.206 +
1.207 +# if !defined(MOZILLA_PRESUME_ARMV7)
1.208 +static bool
1.209 +check_armv7(void)
1.210 +{
1.211 + return (arm_cpu_flags & MOZILLA_HAS_ARMV7_FLAG) != 0;
1.212 +}
1.213 +# endif
1.214 +
1.215 +# if !defined(MOZILLA_PRESUME_NEON)
1.216 +static bool
1.217 +check_neon(void)
1.218 +{
1.219 + return (arm_cpu_flags & MOZILLA_HAS_NEON_FLAG) != 0;
1.220 +}
1.221 +# endif
1.222 +
1.223 +# endif // defined(__linux__) || defined(ANDROID)
1.224 +
1.225 +}
1.226 +
1.227 +namespace mozilla {
1.228 + namespace arm_private {
1.229 +# if !defined(MOZILLA_PRESUME_EDSP)
1.230 + bool edsp_enabled = check_edsp();
1.231 +# endif
1.232 +# if !defined(MOZILLA_PRESUME_ARMV6)
1.233 + bool armv6_enabled = check_armv6();
1.234 +# endif
1.235 +# if !defined(MOZILLA_PRESUME_ARMV7)
1.236 + bool armv7_enabled = check_armv7();
1.237 +# endif
1.238 +# if !defined(MOZILLA_PRESUME_NEON)
1.239 + bool neon_enabled = check_neon();
1.240 +# endif
1.241 + } // namespace arm_private
1.242 +} // namespace mozilla
1.243 +
1.244 +#endif // MOZILLA_ARM_HAVE_CPUID_DETECTION
