Commit 09b462044f776ed1888403be23ae3a2ccb2443f1
2018-12-04T16:50:31
Windows: NEON detection and intrinsic includes on Visual Studio Visual Studio doesn't define __ARM_ARCH nor _ARM_NEON, but _M_ARM and _M_ARM64, so SDL_HasNEON() was bypassed. PF_ARM_NEON_INSTRUCTIONS_AVAILABLE doesn't see to be defined (but still works when defined as 19).
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diff --git a/include/SDL_cpuinfo.h b/include/SDL_cpuinfo.h
index bbd66db..5e078f2 100644
--- a/include/SDL_cpuinfo.h
+++ b/include/SDL_cpuinfo.h
@@ -54,8 +54,22 @@
#if defined(HAVE_ALTIVEC_H) && defined(__ALTIVEC__) && !defined(__APPLE_ALTIVEC__) && defined(SDL_ENABLE_ALTIVEC_H)
#include <altivec.h>
#endif
-#if defined(__ARM_NEON) && !defined(SDL_DISABLE_ARM_NEON_H)
-#include <arm_neon.h>
+#if !defined(SDL_DISABLE_ARM_NEON_H)
+# if defined(__ARM_NEON)
+# include <arm_neon.h>
+# elif defined(__WINDOWS__) || defined(__WINRT__)
+/* Visual Studio doesn't define __ARM_ARCH, but _M_ARM (if set, always 7), and _M_ARM64 (if set, always 1).
+# if defined(_M_ARM)
+# include <armintr.h>
+# include <arm_neon.h>
+# endif
+# if defined (_M_ARM64)
+# include <armintr.h>
+# include <arm_neon.h>
+# endif
+/* Set __ARM_NEON so that it can be used elsewhere, at compile time */
+# define __ARM_NEON 1
+# endif
#endif
#if defined(__3dNOW__) && !defined(SDL_DISABLE_MM3DNOW_H)
#include <mm3dnow.h>
diff --git a/src/cpuinfo/SDL_cpuinfo.c b/src/cpuinfo/SDL_cpuinfo.c
index 7abf408..a0d560a 100644
--- a/src/cpuinfo/SDL_cpuinfo.c
+++ b/src/cpuinfo/SDL_cpuinfo.c
@@ -352,8 +352,18 @@ CPU_haveNEON(void)
{
/* The way you detect NEON is a privileged instruction on ARM, so you have
query the OS kernel in a platform-specific way. :/ */
-#if defined(SDL_CPUINFO_DISABLED) || !defined(__ARM_ARCH)
- return 0; /* disabled or not an ARM CPU at all. */
+#if defined(SDL_CPUINFO_DISABLED)
+ return 0; /* disabled */
+#elif (defined(__WINDOWS__) || defined(__WINRT__)) && (defined(_M_ARM) || defined(_M_ARM64))
+/* Visual Studio, for ARM, doesn't define __ARM_ARCH. Handle this first. */
+/* Seems to have been removed */
+# if !defined(PF_ARM_NEON_INSTRUCTIONS_AVAILABLE)
+# define PF_ARM_NEON_INSTRUCTIONS_AVAILABLE 19
+# endif
+/* All WinRT ARM devices are required to support NEON, but just in case. */
+ return IsProcessorFeaturePresent(PF_ARM_NEON_INSTRUCTIONS_AVAILABLE) != 0;
+#elif !defined(__ARM_ARCH)
+ return 0; /* not an ARM CPU at all. */
#elif __ARM_ARCH >= 8
return 1; /* ARMv8 always has non-optional NEON support. */
#elif defined(__APPLE__) && (__ARM_ARCH >= 7)
@@ -379,9 +389,6 @@ CPU_haveNEON(void)
}
return 0;
}
-#elif (defined(__WINDOWS__) || defined(__WINRT__)) && defined(_M_ARM)
- /* All WinRT ARM devices are required to support NEON, but just in case. */
- return IsProcessorFeaturePresent(PF_ARM_NEON_INSTRUCTIONS_AVAILABLE) != 0;
#else
#warning SDL_HasNEON is not implemented for this ARM platform. Write me.
return 0;