Merge pull request #2282 from martin-frbg/issue2281

Optimize RPCC function on ARM64

Author: martin-frbg

common_arm64.h

@@ -78,7 +78,18 @@ static void __inline blas_lock(volatile BLASULONG *address){
 
 #define BLAS_LOCK_DEFINED
 
+#if !defined(OS_DARWIN) && !defined (OS_ANDROID)
+static __inline BLASULONG rpcc(void){
+  BLASULONG ret = 0;
+ 
+  __asm__ __volatile__ ("isb; mrs %0,cntvct_el0":"=r"(ret));
 
+  return ret;
+}
+
+#define RPCC_DEFINED
+#define RPCC64BIT
+#endif 
 
 static inline int blas_quickdivide(blasint x, blasint y){
   return x / y;