X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmisc.cpp;h=7ed4b443370ac5bf359deb13799fe679bbb22309;hp=bf8143a33462780ac15e61fb3b9ddd4b6b8bc420;hb=a010d438a2e378a82943835d49a53dfaa15c95d1;hpb=cb08413dc4e51ac246887613184b51b46bf11226

diff --git a/src/misc.cpp b/src/misc.cpp
index bf8143a3..7ed4b443 100644
--- a/src/misc.cpp
+++ b/src/misc.cpp
@@ -1,7 +1,7 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2009 Marco Costalba
+  Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -39,6 +39,10 @@
 
 #endif
 
+#if !defined(NO_PREFETCH)
+#  include <xmmintrin.h>
+#endif
+
 #include <cassert>
 #include <cstdio>
 #include <iomanip>
@@ -47,6 +51,7 @@
 
 #include "bitcount.h"
 #include "misc.h"
+#include "thread.h"
 
 using namespace std;
 
@@ -188,7 +193,7 @@ int get_system_time() {
 
 #  if defined(_SC_NPROCESSORS_ONLN)
 int cpu_count() {
-  return Min(sysconf(_SC_NPROCESSORS_ONLN), 8);
+  return Min(sysconf(_SC_NPROCESSORS_ONLN), MAX_THREADS);
 }
 #  elif defined(__hpux)
 int cpu_count() {
@@ -196,7 +201,7 @@ int cpu_count() {
   if (pstat_getdynamic(&psd, sizeof(psd), (size_t)1, 0) == -1)
       return 1;
 
-  return Min(psd.psd_proc_cnt, 8);
+  return Min(psd.psd_proc_cnt, MAX_THREADS);
 }
 #  else
 int cpu_count() {
@@ -209,7 +214,7 @@ int cpu_count() {
 int cpu_count() {
   SYSTEM_INFO s;
   GetSystemInfo(&s);
-  return Min(s.dwNumberOfProcessors, 8);
+  return Min(s.dwNumberOfProcessors, MAX_THREADS);
 }
 
 #endif
@@ -286,4 +291,27 @@ int Bioskey()
         return 0;
     }
 }
+
 #endif
+
+/// prefetch() preloads the given address in L1/L2 cache. This is a non
+/// blocking function and do not stalls the CPU waiting for data to be
+/// loaded from RAM, that can be very slow.
+#if defined(NO_PREFETCH)
+void prefetch(char*) {}
+#else
+
+void prefetch(char* addr) {
+
+#if defined(__INTEL_COMPILER) || defined(__ICL)
+   // This hack prevents prefetches to be optimized away by
+   // Intel compiler. Both MSVC and gcc seems not affected.
+   __asm__ ("");
+#endif
+
+  _mm_prefetch(addr, _MM_HINT_T2);
+  _mm_prefetch(addr+64, _MM_HINT_T2); // 64 bytes ahead
+}
+
+#endif
+