shithub: openh264

Download patch

ref: ef7e05d47d4c002d5a22dbd2aaba33bdedd32964
parent: adb27ff0b1d407ad467ed53811a481bf1199db91
author: Martin Storsjö <martin@martin.st>
date: Fri Feb 28 20:35:21 EST 2014

Use the __ARM_NEON__ built-in compiler define for identifying neon capability on iOS

This avoids having to hardcode the names of devices that don't
support neon.

The devices that don't support neon don't run the armv7 variants
of iOS binaries at all - they would need to be built for the armv6
architecture. (Building for armv6 isn't supported at all in
modern iOS SDKs.)

Therefore we can simply use the __ARM_NEON__ built-in compiler
define to check if NEON code is allowed in the current build,
and have the WelsCPUFeatureDetect function return flags accordingly.

The only thing this disallows is doing an armv6 build which would
optionally enable neon code at runtime if run on an armv7 capable
device, but since Apple allows you to build the same binary for
armv7 separately in the same app bundle, and since armv6 building
isn't even possible in the current iOS SDKs, this isn't really a loss.

This is in contrast to the android builds where the armv7 baseline
does not include NEON.

--- a/codec/common/cpu.cpp

+++ b/codec/common/cpu.cpp

@@ -42,9 +42,6 @@

 #ifdef ANDROID_NDK

 #include <cpu-features.h>

 #endif

-#ifdef APPLE_IOS

-#include <sys/utsname.h>

-#endif

 #include "cpu.h"

 #include "cpu_core.h"

@@ -245,18 +242,12 @@

 uint32_t WelsCPUFeatureDetect (int32_t* pNumberOfLogicProcessors)

 {

     uint32_t       uiCPU = 0;

-    struct utsname sSystemInfo;

-    uname (&sSystemInfo);

-    if ((0 != strcmp(sSystemInfo.machine, "iPhone1,1")) && //iPhone 2G

-        (0 != strcmp(sSystemInfo.machine, "iPhone1,2")) && //iPhone 3G

-        (0 != strcmp(sSystemInfo.machine, "iPod1,1")) &&   //iPod 1G

-        (0 != strcmp(sSystemInfo.machine, "iPod2,1")))     //iPod 2G

-    {

-        uiCPU |= WELS_CPU_ARMv7;

-        uiCPU |= WELS_CPU_VFPv3;

-        uiCPU |= WELS_CPU_NEON;

-    }

+#if defined(__ARM_NEON__)

+    uiCPU |= WELS_CPU_ARMv7;

+    uiCPU |= WELS_CPU_VFPv3;

+    uiCPU |= WELS_CPU_NEON;

+#endif

     return uiCPU;

 }

 #elif defined(__linux__)