exposing branch misses under macos (#587)

* exposing branch misses under macos

* formatting

Author: lemire

benchmarks/performancecounters/apple_arm_events.h

@@ -1102,7 +1102,7 @@ struct AppleEvents {
         printf("%14s: %llu\n", alias->alias, val);
     }*/
     return performance_counters{
-        counters_0[counter_map[0]], counters_0[counter_map[3]],
+        counters_0[counter_map[0]], counters_0[counter_map[2]],
         counters_0[counter_map[2]], counters_0[counter_map[1]]};
   }
 };

benchmarks/performancecounters/event_counter.h

@@ -35,6 +35,8 @@ struct event_count {
   enum event_counter_types {
     CPU_CYCLES,
     INSTRUCTIONS,
+    BRANCH_MISSES = 2,
+    BRANCH = 4
   };
 
   double elapsed_sec() const {
@@ -49,7 +51,10 @@ struct event_count {
   double instructions() const {
     return static_cast<double>(event_counts[INSTRUCTIONS]);
   }
-
+  double branches() const { return static_cast<double>(event_counts[BRANCH]); }
+  double branch_misses() const {
+    return static_cast<double>(event_counts[BRANCH_MISSES]);
+  }
   event_count& operator=(const event_count& other) {
     this->elapsed = other.elapsed;
     this->event_counts = other.event_counts;