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cpu_id using one variable and make it more public how to set flags to disable SIMD

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BUG=none
TEST=scale unittest in talk disables SSSE3
Review URL: http://webrtc-codereview.appspot.com/239018

git-svn-id: http://libyuv.googlecode.com/svn/trunk@47 16f28f9a-4ce2-e073-06de-1de4eb20be90
This commit is contained in:
fbarchard@google.com 2011-10-29 00:18:58 +00:00
parent 585a126140
commit 891091c6d4
2 changed files with 17 additions and 13 deletions
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5
include/libyuv/cpu_id.h
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@ -17,14 +17,15 @@ namespace libyuv {
static const int kCpuHasSSE2 = 1;
static const int kCpuHasSSSE3 = 2;
// SIMD support on ARM processors
// These flags are only valid on ARM processors
static const int kCpuHasNEON = 4;
// Detect CPU has SSE2 etc.
bool TestCpuFlag(int flag);
// For testing, allow CPU flags to be disabled.
void MaskCpuFlagsForTest(int enable_flags);
// ie MaskCpuFlags(~kCpuHasSSSE3) to disable SSSE3. -1 to enable all.
void MaskCpuFlags(int enable_flags);
} // namespace libyuv

25
source/cpu_id.cc
View File

@ -15,6 +15,9 @@
#include <intrin.h>
#endif
// Internal flag to indicate cpuid is initialized.
static const int kCpuInitialized = 16;
// TODO(fbarchard): Use cpuid.h when gcc 4.4 is used on OSX and Linux.
#if (defined(__pic__) || defined(__APPLE__)) && defined(__i386__)
static inline void __cpuid(int cpu_info[4], int info_type) {
@ -39,33 +42,33 @@ static inline void __cpuid(int cpu_info[4], int info_type) {
namespace libyuv {
// CPU detect function for SIMD instruction sets.
static bool cpu_info_initialized_ = false;
static int cpu_info_ = 0;
// Global lock for cpu initialization.
// TODO(fbarchard): (cpu_info[2] & 0x10000000 ? kCpuHasAVX : 0)
static void InitCpuFlags() {
#ifdef CPU_X86
int cpu_info[4];
__cpuid(cpu_info, 1);
cpu_info_ = (cpu_info[2] & 0x00000200 ? kCpuHasSSSE3 : 0) |
(cpu_info[3] & 0x04000000 ? kCpuHasSSE2 : 0);
cpu_info_ = (cpu_info[3] & 0x04000000 ? kCpuHasSSE2 : 0) |
(cpu_info[2] & 0x00000200 ? kCpuHasSSSE3 : 0) |
kCpuInitialized;
#elif defined(__ARM_NEON__)
// gcc -mfpu=neon defines __ARM_NEON__
// if code is specifically built for Neon-only, enable the flag.
cpu_info_ |= kCpuHasNEON;
// Enable Neon if you want support for Neon and Arm, and use MaskCpuFlags
// to disable Neon on devices that do not have it.
cpu_info_ = kCpuHasNEON | kCpuInitialized;
#else
cpu_info_ = 0;
cpu_info_ = kCpuInitialized;
#endif
cpu_info_initialized_ = true;
}
void MaskCpuFlagsForTest(int enable_flags) {
void MaskCpuFlags(int enable_flags) {
InitCpuFlags();
cpu_info_ &= enable_flags;
cpu_info_ = (cpu_info_ & enable_flags) | kCpuInitialized;
}
bool TestCpuFlag(int flag) {
if (!cpu_info_initialized_) {
if (!cpu_info_) {
InitCpuFlags();
}
return cpu_info_ & flag ? true : false;