/media/libvpx/vpx_ports/arm_cpudetect.c
http://github.com/zpao/v8monkey · C · 190 lines · 152 code · 11 blank · 27 comment · 34 complexity · 4fe0f5ecbd696637666e11b14d275665 MD5 · raw file
- /*
- * 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