From: Marco Costalba <mcostalba@gmail.com>
Date: Mon, 3 Jan 2011 09:49:33 +0000 (+0100)
Subject: Readd SRWLOCK and Condition Variables under Windows
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=5973e0985425c90c72b98d75f3ccbd1c1bb3d446

Readd SRWLOCK and Condition Variables under Windows

And set them as default.

Introduce compile switch OLD_LOCKS to allow to fallback on
compatible locks supported by Windows XP and older versions.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
---

diff --git a/src/lock.h b/src/lock.h
index 334bc7c9..9bf59afa 100644
--- a/src/lock.h
+++ b/src/lock.h
@@ -44,6 +44,25 @@ typedef pthread_cond_t WaitCondition;
 #include <windows.h>
 #undef WIN32_LEAN_AND_MEAN
 
+// Default fast and race free locks and condition variables
+#if !defined(OLD_LOCKS)
+
+typedef SRWLOCK Lock;
+typedef CONDITION_VARIABLE WaitCondition;
+
+#  define lock_init(x) InitializeSRWLock(x)
+#  define lock_grab(x) AcquireSRWLockExclusive(x)
+#  define lock_release(x) ReleaseSRWLockExclusive(x)
+#  define lock_destroy(x) (x)
+#  define cond_destroy(x) (x)
+#  define cond_init(x) InitializeConditionVariable(x)
+#  define cond_signal(x) WakeConditionVariable(x)
+#  define cond_wait(x,y) SleepConditionVariableSRW(x, y, INFINITE,0)
+
+// Fallback solution to build for Windows XP and older versions, note that
+// cond_wait() is racy between lock_release() and WaitForSingleObject().
+#else
+
 typedef CRITICAL_SECTION Lock;
 typedef HANDLE WaitCondition;
 
@@ -57,4 +76,6 @@ typedef HANDLE WaitCondition;
 #  define cond_wait(x,y) { lock_release(y); WaitForSingleObject(*x, INFINITE); lock_grab(y); }
 #endif
 
+#endif
+
 #endif // !defined(LOCK_H_INCLUDED)
diff --git a/src/types.h b/src/types.h
index 8e6356eb..d6c7d10a 100644
--- a/src/types.h
+++ b/src/types.h
@@ -70,6 +70,10 @@ typedef uint64_t Bitboard;
 //// -DUSE_POPCNT   | Add runtime support for use of popcnt asm-instruction.
 ////                | Works only in 64-bit mode. For compiling requires hardware
 ////                | with popcnt support. Around 4% speed-up.
+////
+//// -DOLD_LOCKS    | By default under Windows are used the fast Slim Reader/Writer (SRW)
+////                | Locks and Condition Variables: these are not supported by Windows XP
+////                | and older, to compile for those platforms you should enable OLD_LOCKS.
 
 // Automatic detection for 64-bit under Windows
 #if defined(_WIN64)