Cache the results of slow math operations on machines that don't...

src/heap.cc

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 239 matching lines @@
 #elif defined(DEBUG)
   if (FLAG_heap_stats) ReportHeapStatistics("After GC");
 #elif defined(ENABLE_LOGGING_AND_PROFILING)
   if (FLAG_log_gc) new_space_.ReportStatistics();
 #endif
 }
 #endif  // defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
 
 
 void Heap::GarbageCollectionPrologue() {
+  TranscendentalCache::Clear();
   gc_count_++;
 #ifdef DEBUG
   ASSERT(allocation_allowed_ && gc_state_ == NOT_IN_GC);
   allow_allocation(false);
 
   if (FLAG_verify_heap) {
     Verify();
   }
 
   if (FLAG_gc_verbose) Print();
@@ skipping 3709 matching lines @@
 
 #ifdef DEBUG
 bool Heap::GarbageCollectionGreedyCheck() {
   ASSERT(FLAG_gc_greedy);
   if (Bootstrapper::IsActive()) return true;
   if (disallow_allocation_failure()) return true;
   return CollectGarbage(0, NEW_SPACE);
 }
 #endif
 
+
+TranscendentalCache::TranscendentalCache(TranscendentalCache::Type t)
+  : type_(t) {
+  uint32_t in0 = 0xffffffffu;  // Bit-pattern for a NaN that isn't
+  uint32_t in1 = 0xffffffffu;  // generated by the FPU.
+  for (int i = 0; i < kCacheSize; i++) {

[Søren Thygesen Gjesse, 2009/09/01 08:40:31]

Would memcpy be faster here?

[Erik Corry, 2009/09/01 09:02:28]

Possibly, but I don't expect this function to be called all that often, and it
would look messier.

+    elements_[i].in[0] = in0;
+    elements_[i].in[1] = in1;
+    elements_[i].output = NULL;
+  }
+}
+
+
+TranscendentalCache* TranscendentalCache::caches_[kNumberOfCaches];
+
+
+void TranscendentalCache::Clear() {
+  for (int i = 0; i < kNumberOfCaches; i++) {
+    if (caches_[i] != NULL) {
+      delete caches_[i];
+      caches_[i] = NULL;
+    }
+  }
+}
+
+
 } }  // namespace v8::internal