ref: 8c48c943e7c082b4330061e74ce85547253de301
dir: /vpx_ports/arm_cpudetect.c/
/* * Copyright (c) 2010 The WebM project authors. All Rights Reserved. * * Use of this source code is governed by a BSD-style license * that can be found in the LICENSE file in the root of the source * tree. An additional intellectual property rights grant can be found * in the file PATENTS. All contributing project authors may * be found in the AUTHORS file in the root of the source tree. */ #include <stdlib.h> #include <string.h> #include "arm.h" static int arm_cpu_env_flags(int *flags) { char *env; env = getenv("VPX_SIMD_CAPS"); if (env && *env) { *flags = (int)strtol(env, NULL, 0); return 0; } *flags = 0; return -1; } static int arm_cpu_env_mask(void) { char *env; env = getenv("VPX_SIMD_CAPS_MASK"); return env && *env ? (int)strtol(env, NULL, 0) : ~0; } #if defined(_MSC_VER) /*For GetExceptionCode() and EXCEPTION_ILLEGAL_INSTRUCTION.*/ #define WIN32_LEAN_AND_MEAN #define WIN32_EXTRA_LEAN #include <windows.h> int arm_cpu_caps(void) { int flags; int mask; if (!arm_cpu_env_flags(&flags)) { return flags; } mask = arm_cpu_env_mask(); /* MSVC has no inline __asm support for ARM, but it does let you __emit * instructions via their assembled hex code. * All of these instructions should be essentially nops. */ #if defined(HAVE_ARMV5TE) if (mask & HAS_EDSP) { __try { /*PLD [r13]*/ __emit(0xF5DDF000); flags |= HAS_EDSP; } __except(GetExceptionCode() == EXCEPTION_ILLEGAL_INSTRUCTION) { /*Ignore exception.*/ } } #if defined(HAVE_ARMV6) if (mask & HAS_MEDIA) __try { /*SHADD8 r3,r3,r3*/ __emit(0xE6333F93); flags |= HAS_MEDIA; } __except(GetExceptionCode() == EXCEPTION_ILLEGAL_INSTRUCTION) { /*Ignore exception.*/ } } #if defined(HAVE_ARMV7) if (mask & HAS_NEON) { __try { /*VORR q0,q0,q0*/ __emit(0xF2200150); flags |= HAS_NEON; } __except(GetExceptionCode() == EXCEPTION_ILLEGAL_INSTRUCTION) { /*Ignore exception.*/ } } #endif #endif #endif return flags & mask; } #elif defined(__linux__) #include <stdio.h> int arm_cpu_caps(void) { FILE *fin; int flags; int mask; if (!arm_cpu_env_flags(&flags)) { return flags; } mask = arm_cpu_env_mask(); /* Reading /proc/self/auxv would be easier, but that doesn't work reliably * on Android. * This also means that detection will fail in Scratchbox. */ fin = fopen("/proc/cpuinfo","r"); if(fin != NULL) { /* 512 should be enough for anybody (it's even enough for all the flags * that x86 has accumulated... so far). */ char buf[512]; while (fgets(buf, 511, fin) != NULL) { #if defined(HAVE_ARMV5TE) || defined(HAVE_ARMV7) if (memcmp(buf, "Features", 8) == 0) { char *p; #if defined(HAVE_ARMV5TE) p=strstr(buf, " edsp"); if (p != NULL && (p[5] == ' ' || p[5] == '\n')) { flags |= HAS_EDSP; } #if defined(HAVE_ARMV7) p = strstr(buf, " neon"); if (p != NULL && (p[5] == ' ' || p[5] == '\n')) { flags |= HAS_NEON; } #endif #endif } #endif #if defined(HAVE_ARMV6) if (memcmp(buf, "CPU architecture:",17) == 0){ int version; version = atoi(buf+17); if (version >= 6) { flags |= HAS_MEDIA; } } #endif } fclose(fin); } return flags & mask; } #elif !CONFIG_RUNTIME_CPU_DETECT int arm_cpu_caps(void) { int flags; int mask; if (!arm_cpu_env_flags(&flags)) { return flags; } mask = arm_cpu_env_mask(); #if defined(HAVE_ARMV5TE) flags |= HAS_EDSP; #endif #if defined(HAVE_ARMV6) flags |= HAS_MEDIA; #endif #if defined(HAVE_ARMV7) flags |= HAS_NEON; #endif return flags & mask; } #else #error "--enable-runtime-cpu-detect selected, but no CPU detection method " \ "available for your platform. Reconfigure without --enable-runtime-cpu-detect." #endif