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authorErlang/OTP <[email protected]>2009-11-20 14:54:40 +0000
committerErlang/OTP <[email protected]>2009-11-20 14:54:40 +0000
commit84adefa331c4159d432d22840663c38f155cd4c1 (patch)
treebff9a9c66adda4df2106dfd0e5c053ab182a12bd /erts/include/internal/sparc32/rwlock.h
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The R13B03 release.OTP_R13B03
Diffstat (limited to 'erts/include/internal/sparc32/rwlock.h')
-rw-r--r--erts/include/internal/sparc32/rwlock.h142
1 files changed, 142 insertions, 0 deletions
diff --git a/erts/include/internal/sparc32/rwlock.h b/erts/include/internal/sparc32/rwlock.h
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@@ -0,0 +1,142 @@
+/*
+ * %CopyrightBegin%
+ *
+ * Copyright Ericsson AB 2005-2009. All Rights Reserved.
+ *
+ * The contents of this file are subject to the Erlang Public License,
+ * Version 1.1, (the "License"); you may not use this file except in
+ * compliance with the License. You should have received a copy of the
+ * Erlang Public License along with this software. If not, it can be
+ * retrieved online at http://www.erlang.org/.
+ *
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+ * the License for the specific language governing rights and limitations
+ * under the License.
+ *
+ * %CopyrightEnd%
+ */
+
+/*
+ * Native ethread rwlocks on SPARC V9.
+ * Author: Mikael Pettersson.
+ */
+#ifndef ETHREAD_SPARC32_RWLOCK_H
+#define ETHREAD_SPARC32_RWLOCK_H
+
+/* Unlocked if zero, read-locked if positive, write-locked if -1. */
+typedef struct {
+ volatile int lock;
+} ethr_native_rwlock_t;
+
+#ifdef ETHR_TRY_INLINE_FUNCS
+
+static ETHR_INLINE void
+ethr_native_rwlock_init(ethr_native_rwlock_t *lock)
+{
+ lock->lock = 0;
+}
+
+static ETHR_INLINE void
+ethr_native_read_unlock(ethr_native_rwlock_t *lock)
+{
+ unsigned int old, new;
+
+ __asm__ __volatile__("membar #LoadLoad|#StoreLoad");
+ do {
+ old = lock->lock;
+ new = old-1;
+ __asm__ __volatile__(
+ "cas [%2], %1, %0"
+ : "=&r"(new)
+ : "r"(old), "r"(&lock->lock), "0"(new)
+ : "memory");
+ } while (__builtin_expect(old != new, 0));
+}
+
+static ETHR_INLINE int
+ethr_native_read_trylock(ethr_native_rwlock_t *lock)
+{
+ int old, new;
+
+ do {
+ old = lock->lock;
+ if (__builtin_expect(old < 0, 0))
+ return 0;
+ new = old+1;
+ __asm__ __volatile__(
+ "cas [%2], %1, %0"
+ : "=&r"(new)
+ : "r"(old), "r"(&lock->lock), "0"(new)
+ : "memory");
+ } while (__builtin_expect(old != new, 0));
+ __asm__ __volatile__("membar #StoreLoad|#StoreStore");
+ return 1;
+}
+
+static ETHR_INLINE int
+ethr_native_read_is_locked(ethr_native_rwlock_t *lock)
+{
+ return lock->lock < 0;
+}
+
+static ETHR_INLINE void
+ethr_native_read_lock(ethr_native_rwlock_t *lock)
+{
+ for(;;) {
+ if (__builtin_expect(ethr_native_read_trylock(lock) != 0, 1))
+ break;
+ do {
+ __asm__ __volatile__("membar #LoadLoad");
+ } while (ethr_native_read_is_locked(lock));
+ }
+}
+
+static ETHR_INLINE void
+ethr_native_write_unlock(ethr_native_rwlock_t *lock)
+{
+ __asm__ __volatile__("membar #LoadStore|#StoreStore");
+ lock->lock = 0;
+}
+
+static ETHR_INLINE int
+ethr_native_write_trylock(ethr_native_rwlock_t *lock)
+{
+ unsigned int old, new;
+
+ do {
+ old = lock->lock;
+ if (__builtin_expect(old != 0, 0))
+ return 0;
+ new = -1;
+ __asm__ __volatile__(
+ "cas [%2], %1, %0"
+ : "=&r"(new)
+ : "r"(old), "r"(&lock->lock), "0"(new)
+ : "memory");
+ } while (__builtin_expect(old != new, 0));
+ __asm__ __volatile__("membar #StoreLoad|#StoreStore");
+ return 1;
+}
+
+static ETHR_INLINE int
+ethr_native_write_is_locked(ethr_native_rwlock_t *lock)
+{
+ return lock->lock != 0;
+}
+
+static ETHR_INLINE void
+ethr_native_write_lock(ethr_native_rwlock_t *lock)
+{
+ for(;;) {
+ if (__builtin_expect(ethr_native_write_trylock(lock) != 0, 1))
+ break;
+ do {
+ __asm__ __volatile__("membar #LoadLoad");
+ } while (ethr_native_write_is_locked(lock));
+ }
+}
+
+#endif /* ETHR_TRY_INLINE_FUNCS */
+
+#endif /* ETHREAD_SPARC32_RWLOCK_H */