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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/i386/atomic.h
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The R13B03 release.OTP_R13B03
Diffstat (limited to 'erts/include/internal/i386/atomic.h')
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diff --git a/erts/include/internal/i386/atomic.h b/erts/include/internal/i386/atomic.h
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+/*
+ * %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 atomics on x86/x86-64.
+ * Author: Mikael Pettersson.
+ *
+ * This code requires a 486 or newer processor.
+ */
+#ifndef ETHREAD_I386_ATOMIC_H
+#define ETHREAD_I386_ATOMIC_H
+
+/* An atomic is an aligned long accessed via locked operations.
+ */
+typedef struct {
+ volatile long counter;
+} ethr_native_atomic_t;
+
+#ifdef ETHR_TRY_INLINE_FUNCS
+
+#ifdef __x86_64__
+#define LONG_SUFFIX "q"
+#else
+#define LONG_SUFFIX "l"
+#endif
+
+static ETHR_INLINE void
+ethr_native_atomic_init(ethr_native_atomic_t *var, long i)
+{
+ var->counter = i;
+}
+#define ethr_native_atomic_set(v, i) ethr_native_atomic_init((v), (i))
+
+static ETHR_INLINE long
+ethr_native_atomic_read(ethr_native_atomic_t *var)
+{
+ return var->counter;
+}
+
+static ETHR_INLINE void
+ethr_native_atomic_add(ethr_native_atomic_t *var, long incr)
+{
+ __asm__ __volatile__(
+ "lock; add" LONG_SUFFIX " %1, %0"
+ : "=m"(var->counter)
+ : "ir"(incr), "m"(var->counter));
+}
+
+static ETHR_INLINE void
+ethr_native_atomic_inc(ethr_native_atomic_t *var)
+{
+ __asm__ __volatile__(
+ "lock; inc" LONG_SUFFIX " %0"
+ : "=m"(var->counter)
+ : "m"(var->counter));
+}
+
+static ETHR_INLINE void
+ethr_native_atomic_dec(ethr_native_atomic_t *var)
+{
+ __asm__ __volatile__(
+ "lock; dec" LONG_SUFFIX " %0"
+ : "=m"(var->counter)
+ : "m"(var->counter));
+}
+
+static ETHR_INLINE long
+ethr_native_atomic_add_return(ethr_native_atomic_t *var, long incr)
+{
+ long tmp;
+
+ tmp = incr;
+ __asm__ __volatile__(
+ "lock; xadd" LONG_SUFFIX " %0, %1" /* xadd didn't exist prior to the 486 */
+ : "=r"(tmp)
+ : "m"(var->counter), "0"(tmp));
+ /* now tmp is the atomic's previous value */
+ return tmp + incr;
+}
+
+#define ethr_native_atomic_inc_return(var) ethr_native_atomic_add_return((var), 1)
+#define ethr_native_atomic_dec_return(var) ethr_native_atomic_add_return((var), -1)
+
+static ETHR_INLINE long
+ethr_native_atomic_cmpxchg(ethr_native_atomic_t *var, long new, long old)
+{
+ __asm__ __volatile__(
+ "lock; cmpxchg" LONG_SUFFIX " %2, %3"
+ : "=a"(old), "=m"(var->counter)
+ : "r"(new), "m"(var->counter), "0"(old)
+ : "cc", "memory"); /* full memory clobber to make this a compiler barrier */
+ return old;
+}
+
+static ETHR_INLINE long
+ethr_native_atomic_and_retold(ethr_native_atomic_t *var, long mask)
+{
+ long tmp, old;
+
+ tmp = var->counter;
+ do {
+ old = tmp;
+ tmp = ethr_native_atomic_cmpxchg(var, tmp & mask, tmp);
+ } while (__builtin_expect(tmp != old, 0));
+ /* now tmp is the atomic's previous value */
+ return tmp;
+}
+
+static ETHR_INLINE long
+ethr_native_atomic_or_retold(ethr_native_atomic_t *var, long mask)
+{
+ long tmp, old;
+
+ tmp = var->counter;
+ do {
+ old = tmp;
+ tmp = ethr_native_atomic_cmpxchg(var, tmp | mask, tmp);
+ } while (__builtin_expect(tmp != old, 0));
+ /* now tmp is the atomic's previous value */
+ return tmp;
+}
+
+static ETHR_INLINE long
+ethr_native_atomic_xchg(ethr_native_atomic_t *var, long val)
+{
+ long tmp = val;
+ __asm__ __volatile__(
+ "xchg" LONG_SUFFIX " %0, %1"
+ : "=r"(tmp)
+ : "m"(var->counter), "0"(tmp));
+ /* now tmp is the atomic's previous value */
+ return tmp;
+}
+
+#undef LONG_SUFFIX
+
+#endif /* ETHR_TRY_INLINE_FUNCS */
+
+#endif /* ETHREAD_I386_ATOMIC_H */