The R13B03 release.OTP_R13B03

1 files changed, 153 insertions, 0 deletions

diff --git a/erts/include/internal/ppc32/rwlock.h b/erts/include/internal/ppc32/rwlock.h
new file mode 100644
index 0000000000..9bdab12826
--- /dev/null
+++ b/erts/include/internal/ppc32/rwlock.h
@@ -0,0 +1,153 @@
+/*
+ * %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 PowerPC.
+ * Author: Mikael Pettersson.
+ *
+ * Based on the examples in Appendix E of Motorola's
+ * "Programming Environments Manual For 32-Bit Implementations
+ * of the PowerPC Architecture". Uses eieio instead of sync
+ * in the unlock sequence, as suggested in the manual.
+ */
+#ifndef ETHREAD_PPC_RWLOCK_H
+#define ETHREAD_PPC_RWLOCK_H
+
+/* Unlocked if zero, read-locked if negative, 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)
+{
+    int tmp;
+
+    /* this is eieio + ethr_native_atomic_inc() - isync */
+    __asm__ __volatile__(
+	"eieio\n\t"
+	"1:\t"
+	"lwarx	%0,0,%1\n\t"
+	"addic	%0,%0,1\n\t"
+	"stwcx.	%0,0,%1\n\t"
+	"bne-	1b"
+	: "=&r"(tmp)
+	: "r"(&lock->lock)
+	: "cr0", "memory");
+}
+
+static ETHR_INLINE int
+ethr_native_read_trylock(ethr_native_rwlock_t *lock)
+{
+    int counter;
+
+    __asm__ __volatile__(
+	"1:\t"
+	"lwarx	%0,0,%1\n\t"	/* read lock to counter */
+	"addic.	%0,%0,-1\n\t"	/* decrement counter */
+	"bge-	2f\n\t"		/* bail if >= 0 (write-locked) */
+	"stwcx.	%0,0,%1\n\t"	/* try to store decremented counter */
+	"bne-	1b\n\t"		/* loop if lost reservation */
+	"isync\n\t"		/* wait for previous insns to complete */
+	"2:"
+	: "=&r"(counter)
+	: "r"(&lock->lock)
+	: "cr0", "memory"
+#if __GNUC__ > 2
+	,"xer"
+#endif
+	);
+    return counter < 0;
+}
+
+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__("":::"memory");
+	} while (ethr_native_read_is_locked(lock));
+    }
+}
+
+static ETHR_INLINE void
+ethr_native_write_unlock(ethr_native_rwlock_t *lock)
+{
+    __asm__ __volatile__("eieio" : : : "memory");
+    lock->lock = 0;
+}
+
+static ETHR_INLINE int
+ethr_native_write_trylock(ethr_native_rwlock_t *lock)
+{
+    int prev;
+
+    /* identical to ethr_native_spin_trylock() */
+    __asm__ __volatile__(
+	"1:\t"
+	"lwarx	%0,0,%1\n\t"	/* read lock to prev */
+	"cmpwi	0,%0,0\n\t"
+	"bne-	2f\n\t"		/* bail if non-zero (any lock) */
+	"stwcx.	%2,0,%1\n\t"	/* try to make the lock positive */
+	"bne-	1b\n\t"		/* loop if lost reservation */
+	"isync\n\t"		/* wait for previous insns to complete */
+	"2:"
+	: "=&r"(prev)
+	: "r"(&lock->lock), "r"(1)
+	: "cr0", "memory");
+    return prev == 0;
+}
+
+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__("":::"memory");
+	} while (ethr_native_write_is_locked(lock));
+    }
+}
+
+#endif /* ETHR_TRY_INLINE_FUNCS */
+
+#endif /* ETHREAD_PPC_RWLOCK_H */