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comparison: mozglue/build/arm.cpp
mozglue/build/arm.cpp
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- TOR_BUG_9701
- changeset 15
- b8a032363ba2
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| -1:000000000000 | 0:6e976b6e4212 |
|---|---|
| 1 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 2 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 4 | |
| 5 /* compile-time and runtime tests for whether to use various ARM extensions */ | |
| 6 | |
| 7 #include "mozilla/NullPtr.h" | |
| 8 | |
| 9 #include "arm.h" | |
| 10 | |
| 11 #if defined(MOZILLA_ARM_HAVE_CPUID_DETECTION) | |
| 12 namespace { | |
| 13 | |
| 14 // arm.h has parallel #ifs which declare MOZILLA_ARM_HAVE_CPUID_DETECTION. | |
| 15 // We don't check it here so that we get compile errors if it's defined, but | |
| 16 // we don't compile one of these detection methods. The detection code here is | |
| 17 // based on the CPU detection in libtheora. | |
| 18 | |
| 19 # if defined(_MSC_VER) | |
| 20 //For GetExceptionCode() and EXCEPTION_ILLEGAL_INSTRUCTION. | |
| 21 # define WIN32_LEAN_AND_MEAN | |
| 22 # define WIN32_EXTRA_LEAN | |
| 23 # include <windows.h> | |
| 24 | |
| 25 # if !defined(MOZILLA_PRESUME_EDSP) | |
| 26 static bool | |
| 27 check_edsp(void) | |
| 28 { | |
| 29 # if defined(MOZILLA_MAY_SUPPORT_EDSP) | |
| 30 __try | |
| 31 { | |
| 32 //PLD [r13] | |
| 33 __emit(0xF5DDF000); | |
| 34 return true; | |
| 35 } | |
| 36 __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION) | |
| 37 { | |
| 38 //Ignore exception. | |
| 39 } | |
| 40 # endif | |
| 41 return false; | |
| 42 } | |
| 43 # endif // !MOZILLA_PRESUME_EDSP | |
| 44 | |
| 45 # if !defined(MOZILLA_PRESUME_ARMV6) | |
| 46 static bool | |
| 47 check_armv6(void) | |
| 48 { | |
| 49 # if defined(MOZILLA_MAY_SUPPORT_ARMV6) | |
| 50 __try | |
| 51 { | |
| 52 //SHADD8 r3,r3,r3 | |
| 53 __emit(0xE6333F93); | |
| 54 return true; | |
| 55 } | |
| 56 __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION) | |
| 57 { | |
| 58 //Ignore exception. | |
| 59 } | |
| 60 # endif | |
| 61 return false; | |
| 62 } | |
| 63 # endif // !MOZILLA_PRESUME_ARMV6 | |
| 64 | |
| 65 # if !defined(MOZILLA_PRESUME_ARMV7) | |
| 66 static bool | |
| 67 check_armv7(void) | |
| 68 { | |
| 69 # if defined(MOZILLA_MAY_SUPPORT_ARMV7) | |
| 70 __try | |
| 71 { | |
| 72 // ARMv7 DMB (Data Memory Barrier) for stores (DMB.ST) | |
| 73 // The Data Memory Barrier existed before ARMv7 as a | |
| 74 // cp15 operation, but ARMv7 introduced a dedicated | |
| 75 // instruction, DMB. | |
| 76 emit(0xF57FF05E); | |
| 77 return true; | |
| 78 } | |
| 79 __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION) | |
| 80 { | |
| 81 //Ignore exception. | |
| 82 } | |
| 83 # endif | |
| 84 return false; | |
| 85 } | |
| 86 # endif // !MOZILLA_PRESUME_ARMV7 | |
| 87 | |
| 88 # if !defined(MOZILLA_PRESUME_NEON) | |
| 89 static bool | |
| 90 check_neon(void) | |
| 91 { | |
| 92 # if defined(MOZILLA_MAY_SUPPORT_NEON) | |
| 93 __try | |
| 94 { | |
| 95 //VORR q0,q0,q0 | |
| 96 __emit(0xF2200150); | |
| 97 return true; | |
| 98 } | |
| 99 __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION) | |
| 100 { | |
| 101 //Ignore exception. | |
| 102 } | |
| 103 # endif | |
| 104 return false; | |
| 105 } | |
| 106 # endif // !MOZILLA_PRESUME_NEON | |
| 107 | |
| 108 # elif defined(__linux__) || defined(ANDROID) | |
| 109 # include <stdio.h> | |
| 110 # include <stdlib.h> | |
| 111 # include <string.h> | |
| 112 | |
| 113 enum{ | |
| 114 MOZILLA_HAS_EDSP_FLAG=1, | |
| 115 MOZILLA_HAS_ARMV6_FLAG=2, | |
| 116 MOZILLA_HAS_ARMV7_FLAG=4, | |
| 117 MOZILLA_HAS_NEON_FLAG=8 | |
| 118 }; | |
| 119 | |
| 120 static unsigned | |
| 121 get_arm_cpu_flags(void) | |
| 122 { | |
| 123 unsigned flags; | |
| 124 FILE *fin; | |
| 125 bool armv6_processor = false; | |
| 126 flags = 0; | |
| 127 /*Reading /proc/self/auxv would be easier, but that doesn't work reliably on | |
| 128 Android. This also means that detection will fail in Scratchbox, which is | |
| 129 desirable, as NEON does not work in the qemu shipped with the Maemo 5 SDK. | |
| 130 I don't know if /proc/self/auxv would do any better in that case, anyway, | |
| 131 or if it would return random flags from the host CPU.*/ | |
| 132 fin = fopen ("/proc/cpuinfo","r"); | |
| 133 if (fin != nullptr) | |
| 134 { | |
| 135 /*512 should be enough for anybody (it's even enough for all the flags that | |
| 136 x86 has accumulated... so far).*/ | |
| 137 char buf[512]; | |
| 138 while (fgets(buf, 511, fin) != nullptr) | |
| 139 { | |
| 140 if (memcmp(buf, "Features", 8) == 0) | |
| 141 { | |
| 142 char *p; | |
| 143 p = strstr(buf, " edsp"); | |
| 144 if (p != nullptr && (p[5] == ' ' || p[5] == '\n')) | |
| 145 flags |= MOZILLA_HAS_EDSP_FLAG; | |
| 146 p = strstr(buf, " neon"); | |
| 147 if( p != nullptr && (p[5] == ' ' || p[5] == '\n')) | |
| 148 flags |= MOZILLA_HAS_NEON_FLAG; | |
| 149 } | |
| 150 if (memcmp(buf, "CPU architecture:", 17) == 0) | |
| 151 { | |
| 152 int version; | |
| 153 version = atoi(buf + 17); | |
| 154 if (version >= 6) | |
| 155 flags |= MOZILLA_HAS_ARMV6_FLAG; | |
| 156 if (version >= 7) | |
| 157 flags |= MOZILLA_HAS_ARMV7_FLAG; | |
| 158 } | |
| 159 /* media/webrtc/trunk/src/system_wrappers/source/cpu_features_arm.c | |
| 160 * Unfortunately, it seems that certain ARMv6-based CPUs | |
| 161 * report an incorrect architecture number of 7! | |
| 162 * | |
| 163 * We try to correct this by looking at the 'elf_format' | |
| 164 * field reported by the 'Processor' field, which is of the | |
| 165 * form of "(v7l)" for an ARMv7-based CPU, and "(v6l)" for | |
| 166 * an ARMv6-one. | |
| 167 */ | |
| 168 if (memcmp(buf, "Processor\t:", 11) == 0) { | |
| 169 if (strstr(buf, "(v6l)") != 0) { | |
| 170 armv6_processor = true; | |
| 171 } | |
| 172 } | |
| 173 } | |
| 174 fclose(fin); | |
| 175 } | |
| 176 if (armv6_processor) { | |
| 177 // ARMv6 pretending to be ARMv7? clear flag | |
| 178 if (flags & MOZILLA_HAS_ARMV7_FLAG) { | |
| 179 flags &= ~MOZILLA_HAS_ARMV7_FLAG; | |
| 180 } | |
| 181 } | |
| 182 return flags; | |
| 183 } | |
| 184 | |
| 185 // Cache a local copy so we only have to read /proc/cpuinfo once. | |
| 186 static unsigned arm_cpu_flags = get_arm_cpu_flags(); | |
| 187 | |
| 188 # if !defined(MOZILLA_PRESUME_EDSP) | |
| 189 static bool | |
| 190 check_edsp(void) | |
| 191 { | |
| 192 return (arm_cpu_flags & MOZILLA_HAS_EDSP_FLAG) != 0; | |
| 193 } | |
| 194 # endif | |
| 195 | |
| 196 # if !defined(MOZILLA_PRESUME_ARMV6) | |
| 197 static bool | |
| 198 check_armv6(void) | |
| 199 { | |
| 200 return (arm_cpu_flags & MOZILLA_HAS_ARMV6_FLAG) != 0; | |
| 201 } | |
| 202 # endif | |
| 203 | |
| 204 # if !defined(MOZILLA_PRESUME_ARMV7) | |
| 205 static bool | |
| 206 check_armv7(void) | |
| 207 { | |
| 208 return (arm_cpu_flags & MOZILLA_HAS_ARMV7_FLAG) != 0; | |
| 209 } | |
| 210 # endif | |
| 211 | |
| 212 # if !defined(MOZILLA_PRESUME_NEON) | |
| 213 static bool | |
| 214 check_neon(void) | |
| 215 { | |
| 216 return (arm_cpu_flags & MOZILLA_HAS_NEON_FLAG) != 0; | |
| 217 } | |
| 218 # endif | |
| 219 | |
| 220 # endif // defined(__linux__) || defined(ANDROID) | |
| 221 | |
| 222 } | |
| 223 | |
| 224 namespace mozilla { | |
| 225 namespace arm_private { | |
| 226 # if !defined(MOZILLA_PRESUME_EDSP) | |
| 227 bool edsp_enabled = check_edsp(); | |
| 228 # endif | |
| 229 # if !defined(MOZILLA_PRESUME_ARMV6) | |
| 230 bool armv6_enabled = check_armv6(); | |
| 231 # endif | |
| 232 # if !defined(MOZILLA_PRESUME_ARMV7) | |
| 233 bool armv7_enabled = check_armv7(); | |
| 234 # endif | |
| 235 # if !defined(MOZILLA_PRESUME_NEON) | |
| 236 bool neon_enabled = check_neon(); | |
| 237 # endif | |
| 238 } // namespace arm_private | |
| 239 } // namespace mozilla | |
| 240 | |
| 241 #endif // MOZILLA_ARM_HAVE_CPUID_DETECTION |
