From aa98e2b37ee1b0a4c4470816cf0817056db66a9d Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@pdimov.com>
Date: Wed, 27 Feb 2002 16:35:15 +0000
Subject: [PATCH] Added lwm_irix.hpp (contributed by Dan Gohman)

[SVN r12955]
---
 include/boost/detail/lightweight_mutex.hpp |  2 +
 include/boost/detail/lwm_irix.hpp          | 78 ++++++++++++++++++++++
 include/boost/detail/lwm_win32.hpp         | 57 ----------------
 3 files changed, 80 insertions(+), 57 deletions(-)
 create mode 100644 include/boost/detail/lwm_irix.hpp

diff --git a/include/boost/detail/lightweight_mutex.hpp b/include/boost/detail/lightweight_mutex.hpp
index d4ef1c1..69a3a6c 100644
--- a/include/boost/detail/lightweight_mutex.hpp
+++ b/include/boost/detail/lightweight_mutex.hpp
@@ -40,6 +40,8 @@
 #  include <boost/detail/lwm_win32.hpp>
 #elif defined(linux) || defined(__linux) || defined(__linux__)
 #  include <boost/detail/lwm_linux.hpp>
+#elif defined(__sgi)
+#  include <boost/detail/lwm_irix.hpp>
 #elif defined(BOOST_HAS_PTHREADS)
 #  include <boost/detail/lwm_pthreads.hpp>
 #else
diff --git a/include/boost/detail/lwm_irix.hpp b/include/boost/detail/lwm_irix.hpp
new file mode 100644
index 0000000..2a55161
--- /dev/null
+++ b/include/boost/detail/lwm_irix.hpp
@@ -0,0 +1,78 @@
+#ifndef BOOST_DETAIL_LWM_IRIX_HPP_INCLUDED
+#define BOOST_DETAIL_LWM_IRIX_HPP_INCLUDED
+
+#if _MSC_VER >= 1020
+#pragma once
+#endif
+
+//
+//  boost/detail/lwm_irix.hpp
+//
+//  Copyright (c) 2002 Peter Dimov and Multi Media Ltd.
+//  Copyright (c) 2002 Dan Gohman
+//
+//  Permission to copy, use, modify, sell and distribute this software
+//  is granted provided this copyright notice appears in all copies.
+//  This software is provided "as is" without express or implied
+//  warranty, and with no claim as to its suitability for any purpose.
+//
+
+#include <sgidefs.h>
+#include <mutex.h>
+#include <sched.h>
+
+namespace boost
+{
+
+namespace detail
+{
+
+class lightweight_mutex
+{
+private:
+
+    __uint32_t l_;
+
+    lightweight_mutex(lightweight_mutex const &);
+    lightweight_mutex & operator=(lightweight_mutex const &);
+
+public:
+
+    lightweight_mutex(): l_(0)
+    {
+    }
+
+    class scoped_lock;
+    friend class scoped_lock;
+
+    class scoped_lock
+    {
+    private:
+
+        lightweight_mutex & m_;
+
+        scoped_lock(scoped_lock const &);
+        scoped_lock & operator=(scoped_lock const &);
+
+    public:
+
+        explicit scoped_lock(lightweight_mutex & m): m_(m)
+        {
+            while( test_and_set32(&m_.l_, 1) )
+            {
+                sched_yield();
+            }
+        }
+
+        ~scoped_lock()
+        {
+            m_.l_ = 0;
+        }
+    };
+};
+
+} // namespace detail
+
+} // namespace boost
+
+#endif // #ifndef BOOST_DETAIL_LWM_IRIX_HPP_INCLUDED
diff --git a/include/boost/detail/lwm_win32.hpp b/include/boost/detail/lwm_win32.hpp
index 8bcd469..3e79198 100644
--- a/include/boost/detail/lwm_win32.hpp
+++ b/include/boost/detail/lwm_win32.hpp
@@ -16,18 +16,12 @@
 //  warranty, and with no claim as to its suitability for any purpose.
 //
 
-#ifndef BOOST_LWM_WIN32_USE_CRITICAL_SECTION
-# include <windows.h>
-#endif
-
 namespace boost
 {
 
 namespace detail
 {
 
-#ifndef BOOST_LWM_WIN32_USE_CRITICAL_SECTION
-
 // avoid including <windows.h>
 
 extern "C" __declspec(dllimport) long __stdcall InterlockedExchange(long volatile *, long);
@@ -80,57 +74,6 @@ public:
     };
 };
 
-#else
-
-class lightweight_mutex
-{
-private:
-
-    CRITICAL_SECTION cs_;
-
-    lightweight_mutex(lightweight_mutex const &);
-    lightweight_mutex & operator=(lightweight_mutex const &);
-
-public:
-
-    lightweight_mutex()
-    {
-        ::InitializeCriticalSection(&cs_);
-    }
-
-    ~lightweight_mutex()
-    {
-        ::DeleteCriticalSection(&cs_);
-    }
-
-    class scoped_lock;
-    friend class scoped_lock;
-
-    class scoped_lock
-    {
-    private:
-
-        lightweight_mutex & m_;
-
-        scoped_lock(scoped_lock const &);
-        scoped_lock & operator=(scoped_lock const &);
-
-    public:
-
-        explicit scoped_lock(lightweight_mutex & m): m_(m)
-        {
-            ::EnterCriticalSection(&m_.cs_);
-        }
-
-        ~scoped_lock()
-        {
-            ::LeaveCriticalSection(&m_.cs_);
-        }
-    };
-};
-
-#endif
-
 } // namespace detail
 
 } // namespace boost