original

[gb-231r1-is01/GB_2.3_IS01.git] / system / core / libcutils / atomic-android-sh.c

diff --git a/system/core/libcutils/atomic-android-sh.c b/system/core/libcutils/atomic-android-sh.c
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+++ b/system/core/libcutils/atomic-android-sh.c
@@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <cutils/atomic.h>
+#ifdef HAVE_WIN32_THREADS
+#include <windows.h>
+#else
+#include <sched.h>
+#endif
+
+/*
+ * Note :
+ *
+ * (1) SuperH does not have CMPXCHG.  It has only TAS for atomic
+ *     operations.  It does not seem a good idea to implement CMPXCHG,
+ *     with TAS.  So, we choose to implemnt these operations with
+ *     posix mutexes.  Please be sure that this might cause performance
+ *     problem for Android-SH. Using LL/SC instructions supported in SH-X3,
+ *     best performnace would be realized.
+ *
+ * (2) Mutex initialization problem happens, which is commented for
+ *     ARM implementation, in this file above.
+ *     We follow the fact that the initializer for mutex is a simple zero
+ *     value.
+ *
+ * (3) These operations are NOT safe for SMP, as there is no currently
+ *     no definition for a memory barrier operation.
+ */
+
+#include <pthread.h>
+
+#define  SWAP_LOCK_COUNT  32U
+static pthread_mutex_t  _swap_locks[SWAP_LOCK_COUNT];
+
+#define  SWAP_LOCK(addr)   \
+   &_swap_locks[((unsigned)(void*)(addr) >> 3U) % SWAP_LOCK_COUNT]
+
+
+int32_t android_atomic_acquire_load(volatile const int32_t* addr)
+{
+    return *addr;
+}
+
+int32_t android_atomic_release_load(volatile const int32_t* addr)
+{
+    return *addr;
+}
+
+void android_atomic_acquire_store(int32_t value, volatile int32_t* addr) {
+    int32_t oldValue;
+    do {
+        oldValue = *addr;
+    } while (android_atomic_release_cas(oldValue, value, addr));
+}
+
+void android_atomic_release_store(int32_t value, volatile int32_t* addr) {
+    int32_t oldValue;
+    do {
+        oldValue = *addr;
+    } while (android_atomic_release_cas(oldValue, value, addr));
+}
+
+int32_t android_atomic_inc(volatile int32_t* addr) {
+    int32_t oldValue;
+    do {
+        oldValue = *addr;
+    } while (android_atomic_release_cas(oldValue, oldValue+1, addr));
+    return oldValue;
+}
+
+int32_t android_atomic_dec(volatile int32_t* addr) {
+    int32_t oldValue;
+    do {
+        oldValue = *addr;
+    } while (android_atomic_release_cas(oldValue, oldValue-1, addr));
+    return oldValue;
+}
+
+int32_t android_atomic_add(int32_t value, volatile int32_t* addr) {
+    int32_t oldValue;
+    do {
+        oldValue = *addr;
+    } while (android_atomic_release_cas(oldValue, oldValue+value, addr));
+    return oldValue;
+}
+
+int32_t android_atomic_and(int32_t value, volatile int32_t* addr) {
+    int32_t oldValue;
+    do {
+        oldValue = *addr;
+    } while (android_atomic_release_cas(oldValue, oldValue&value, addr));
+    return oldValue;
+}
+
+int32_t android_atomic_or(int32_t value, volatile int32_t* addr) {
+    int32_t oldValue;
+    do {
+        oldValue = *addr;
+    } while (android_atomic_release_cas(oldValue, oldValue|value, addr));
+    return oldValue;
+}
+
+int32_t android_atomic_acquire_swap(int32_t value, volatile int32_t* addr) {
+    return android_atomic_release_swap(value, addr);
+}
+
+int32_t android_atomic_release_swap(int32_t value, volatile int32_t* addr) {
+    int32_t oldValue;
+    do {
+        oldValue = *addr;
+    } while (android_atomic_cmpxchg(oldValue, value, addr));
+    return oldValue;
+}
+
+int android_atomic_acquire_cmpxchg(int32_t oldvalue, int32_t newvalue,
+                           volatile int32_t* addr) {
+    return android_atomic_release_cmpxchg(oldValue, newValue, addr);
+}
+
+int android_atomic_release_cmpxchg(int32_t oldvalue, int32_t newvalue,
+                           volatile int32_t* addr) {
+    int result;
+    pthread_mutex_t*  lock = SWAP_LOCK(addr);
+
+    pthread_mutex_lock(lock);
+
+    if (*addr == oldvalue) {
+        *addr  = newvalue;
+        result = 0;
+    } else {
+        result = 1;
+    }
+    pthread_mutex_unlock(lock);
+    return result;
+}
+