From 447762da858c1705c5fce5288f874797dc4b1135 Mon Sep 17 00:00:00 2001
From: "Michael J. Spencer" <bigcheesegs@gmail.com>
Date: Mon, 29 Nov 2010 18:16:10 +0000
Subject: Merge System into Support.

llvm-svn: 120298
---
 llvm/lib/Support/Atomic.cpp | 112 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 llvm/lib/Support/Atomic.cpp

(limited to 'llvm/lib/Support/Atomic.cpp')

diff --git a/llvm/lib/Support/Atomic.cpp b/llvm/lib/Support/Atomic.cpp
new file mode 100644
index 00000000000..c7b4bff2794
--- /dev/null
+++ b/llvm/lib/Support/Atomic.cpp
@@ -0,0 +1,112 @@
+//===-- Atomic.cpp - Atomic Operations --------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This header file implements atomic operations.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/Atomic.h"
+#include "llvm/Config/config.h"
+
+using namespace llvm;
+
+#if defined(_MSC_VER)
+#include <windows.h>
+#undef MemoryFence
+#endif
+
+void sys::MemoryFence() {
+#if LLVM_MULTITHREADED==0
+  return;
+#else
+#  if defined(__GNUC__)
+  __sync_synchronize();
+#  elif defined(_MSC_VER)
+  MemoryBarrier();
+#  else
+# error No memory fence implementation for your platform!
+#  endif
+#endif
+}
+
+sys::cas_flag sys::CompareAndSwap(volatile sys::cas_flag* ptr,
+                                  sys::cas_flag new_value,
+                                  sys::cas_flag old_value) {
+#if LLVM_MULTITHREADED==0
+  sys::cas_flag result = *ptr;
+  if (result == old_value)
+    *ptr = new_value;
+  return result;
+#elif defined(__GNUC__)
+  return __sync_val_compare_and_swap(ptr, old_value, new_value);
+#elif defined(_MSC_VER)
+  return InterlockedCompareExchange(ptr, new_value, old_value);
+#else
+#  error No compare-and-swap implementation for your platform!
+#endif
+}
+
+sys::cas_flag sys::AtomicIncrement(volatile sys::cas_flag* ptr) {
+#if LLVM_MULTITHREADED==0
+  ++(*ptr);
+  return *ptr;
+#elif defined(__GNUC__)
+  return __sync_add_and_fetch(ptr, 1);
+#elif defined(_MSC_VER)
+  return InterlockedIncrement(ptr);
+#else
+#  error No atomic increment implementation for your platform!
+#endif
+}
+
+sys::cas_flag sys::AtomicDecrement(volatile sys::cas_flag* ptr) {
+#if LLVM_MULTITHREADED==0
+  --(*ptr);
+  return *ptr;
+#elif defined(__GNUC__)
+  return __sync_sub_and_fetch(ptr, 1);
+#elif defined(_MSC_VER)
+  return InterlockedDecrement(ptr);
+#else
+#  error No atomic decrement implementation for your platform!
+#endif
+}
+
+sys::cas_flag sys::AtomicAdd(volatile sys::cas_flag* ptr, sys::cas_flag val) {
+#if LLVM_MULTITHREADED==0
+  *ptr += val;
+  return *ptr;
+#elif defined(__GNUC__)
+  return __sync_add_and_fetch(ptr, val);
+#elif defined(_MSC_VER)
+  return InterlockedExchangeAdd(ptr, val) + val;
+#else
+#  error No atomic add implementation for your platform!
+#endif
+}
+
+sys::cas_flag sys::AtomicMul(volatile sys::cas_flag* ptr, sys::cas_flag val) {
+  sys::cas_flag original, result;
+  do {
+    original = *ptr;
+    result = original * val;
+  } while (sys::CompareAndSwap(ptr, result, original) != original);
+
+  return result;
+}
+
+sys::cas_flag sys::AtomicDiv(volatile sys::cas_flag* ptr, sys::cas_flag val) {
+  sys::cas_flag original, result;
+  do {
+    original = *ptr;
+    result = original / val;
+  } while (sys::CompareAndSwap(ptr, result, original) != original);
+
+  return result;
+}
-- 
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