New files to implement atomic operations for different platforms. Fixes

2004-02-26  Sebastian Wilhelmi  <seppi@seppi.de>

	* glib/gatomic.c, glib/gatomic.h: New files to implement atomic
	operations for different platforms. Fixes bug #63621.

	* glib/glib.h: Include gatomic.h.

	* configure.in: Add test for assembler routines for atomic operations.

	* glib/Makefile.am: Add gatomic.c, gatomic.h.

	* tests/Makefile.am, tests/atomic-test.c: Unit test for atomic
	operations.

	* glib/glib-overrides.txt, glib/glib-sections.txt,
	glib/glib-docs.sgml, glib/tmpl/atomic_operations.sgml: Add docs
	for atomic operations.

1 files changed, 545 insertions, 0 deletions

diff --git a/glib/gatomic.h b/glib/gatomic.h
new file mode 100644
index 000000000..1ce92bb9d
--- /dev/null
+++ b/glib/gatomic.h
@@ -0,0 +1,545 @@
+/* GLIB - Library of useful routines for C programming
+ * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
+ *
+ * GAtomic: atomic integer operation.
+ * Copyright (C) 2003 Sebastian Wilhelmi
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+ 
+/*
+ * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
+ * file for a list of people on the GLib Team.  See the ChangeLog
+ * files for a list of changes.  These files are distributed with
+ * GLib at ftp://ftp.gtk.org/pub/gtk/.
+ */
+ 
+#ifndef __G_ATOMIC_H__
+#define __G_ATOMIC_H__
+ 
+#include <glib/gtypes.h>
+
+G_BEGIN_DECLS
+ 
+#ifdef G_THREADS_ENABLED
+
+gint32   g_atomic_int_exchange_and_add_fallback         (gint32   *atomic, 
+							 gint32    val);
+void     g_atomic_int_add_fallback                      (gint32   *atomic, 
+							 gint32    val);
+gboolean g_atomic_int_compare_and_exchange_fallback     (gint32   *atomic, 
+							 gint32    oldval, 
+							 gint32    newval);
+gboolean g_atomic_pointer_compare_and_exchange_fallback (gpointer *atomic, 
+							 gpointer  oldval, 
+							 gpointer  newval);
+
+# if defined (__GNUC__)
+#   if defined (G_ATOMIC_INLINED_IMPLEMENTATION_I486)
+/* Adapted from CVS version 1.10 of glibc's sysdeps/i386/i486/bits/atomic.h 
+ */
+static inline gint32
+g_atomic_int_exchange_and_add (gint32 *atomic, 
+			       gint32 val)
+{
+  gint32 result;
+
+  __asm__ __volatile__ ("lock; xaddl %0,%1"
+                        : "=r" (result), "=m" (*atomic) 
+			: "0" (val), "m" (*atomic));
+  return result;
+}
+ 
+static inline void
+g_atomic_int_add (gint32 *atomic, 
+		  gint32 val)
+{
+  __asm__ __volatile__ ("lock; addl %1,%0"
+			: "=m" (*atomic) 
+			: "ir" (val), "m" (*atomic));
+}
+
+static inline gboolean
+g_atomic_int_compare_and_exchange (gint32 *atomic, 
+				   gint32 oldval, 
+				   gint32 newval)
+{
+  gint32 result;
+ 
+  __asm __volatile ("lock; cmpxchgl %2, %1"
+		    : "=a" (result), "=m" (*atomic)
+		    : "r" (newval), "m" (*atomic), "0" (oldval)); 
+
+  return result == oldval;
+}
+
+/* The same code as above, as on i386 gpointer is 32 bit as well.
+ * Duplicating the code here seems more natural than casting the
+ * arguments and calling the former function */
+
+static inline gboolean
+g_atomic_pointer_compare_and_exchange (gpointer *atomic, 
+				       gpointer  oldval, 
+				       gpointer  newval)
+{
+  gpointer result;
+ 
+  __asm __volatile ("lock; cmpxchgl %2, %1"
+		    : "=a" (result), "=m" (*atomic)
+		    : "r" (newval), "m" (*atomic), "0" (oldval)); 
+
+  return result == oldval;
+}
+
+#      define G_ATOMIC_MEMORY_BARRIER() /* Not needed */
+
+#   elif defined(G_ATOMIC_INLINED_IMPLEMENTATION_SPARCV9) \
+   && (defined(__sparcv8) || defined(__sparcv9) || defined(__sparc_v9__))
+/* Adapted from CVS version 1.3 of glibc's sysdeps/sparc/sparc64/bits/atomic.h
+ */
+/* Why the test for __sparcv8, wheras really the sparcv9 architecture
+ * is required for the folowing assembler instructions? On
+ * sparc-solaris the only difference detectable at compile time
+ * between no -m and -mcpu=v9 is __sparcv8.
+ *
+ * However, in case -mcpu=v8 is set, the assembler will fail. This
+ * should be rare however, as there are only very few v8-not-v9
+ * machines still out there (and we can't do better).
+ */
+static inline gboolean
+g_atomic_int_compare_and_exchange (gint32 *atomic, 
+				   gint32 oldval, 
+				   gint32 newval)
+{
+  gint32 result;
+  __asm __volatile ("cas [%4], %2, %0"
+                    : "=r" (result), "=m" (*atomic)
+                    : "r" (oldval), "m" (*atomic), "r" (atomic),
+                      "0" (newval));
+  return result != 0;
+}
+
+#     if GLIB_SIZEOF_VOID_P == 4 /* 32-bit system */
+static inline gboolean
+g_atomic_pointer_compare_and_exchange (gpointer *atomic, 
+				       gpointer  oldval, 
+				       gpointer  newval)
+{
+  gpointer result;
+  __asm __volatile ("cas [%4], %2, %0"
+                    : "=r" (result), "=m" (*atomic)
+                    : "r" (oldval), "m" (*atomic), "r" (atomic),
+                      "0" (newval));
+  return result != 0;
+}
+#     elif GLIB_SIZEOF_VOID_P == 8 /* 64-bit system */
+static inline gboolean
+g_atomic_pointer_compare_and_exchange (gpointer *atomic, 
+				       gpointer  oldval, 
+				       gpointer  newval)
+{
+  gpointer result;
+  gpointer *a = atomic;
+  __asm __volatile ("casx [%4], %2, %0"
+                    : "=r" (result), "=m" (*a)
+                    : "r" (oldval), "m" (*a), "r" (a),
+                      "0" (newval));
+  return result != 0;
+}
+#     else /* What's that */
+#       error "Your system has an unsupported pointer size"
+#     endif /* GLIB_SIZEOF_VOID_P */
+static inline gint32
+g_atomic_int_exchange_and_add (gint32 *atomic, 
+			       gint32 val)
+{
+  gint32 result;
+  do
+    result = *atomic;
+  while (!g_atomic_int_compare_and_exchange (atomic, result, result + val));
+
+  return result;
+}
+ 
+static inline void
+g_atomic_int_add (gint32 *atomic, 
+		  gint32 val)
+{
+  g_atomic_int_exchange_and_add (atomic, val);
+}
+
+#      define G_ATOMIC_MEMORY_BARRIER()					\
+  __asm __volatile ("membar #LoadLoad | #LoadStore"			\
+                    " | #StoreLoad | #StoreStore" : : : "memory")
+
+#   elif defined(G_ATOMIC_INLINED_IMPLEMENTATION_ALPHA)
+/* Adapted from CVS version 1.3 of glibc's sysdeps/alpha/bits/atomic.h
+ */
+static inline gboolean
+g_atomic_int_compare_and_exchange (gint32 *atomic, 
+				   gint32 oldval, 
+				   gint32 newval)
+{
+  gint32 result;
+  gint32 prev;
+  __asm__ __volatile__ (
+        "       mb\n"
+        "1:     ldl_l   %0,%2\n"
+        "       cmpeq   %0,%3,%1\n"
+        "       beq     %1,2f\n"
+        "       mov     %4,%1\n"
+        "       stl_c   %1,%2\n"
+        "       beq     %1,1b\n"
+        "       mb\n"
+        "2:"
+        : "=&r" (prev), 
+          "=&r" (result)
+        : "m" (*atomic),
+          "Ir" ((gint64)oldval),
+          "Ir" (newval)
+        : "memory");
+  return result != 0;
+}
+#     if GLIB_SIZEOF_VOID_P == 4 /* 32-bit system */
+static inline gboolean
+g_atomic_pointer_compare_and_exchange (gpointer *atomic, 
+				       gpointer  oldval, 
+				       gpointer  newval)
+{
+  gint32 result;
+  gpointer prev;
+  __asm__ __volatile__ (
+        "       mb\n"
+        "1:     ldl_l   %0,%2\n"
+        "       cmpeq   %0,%3,%1\n"
+        "       beq     %1,2f\n"
+        "       mov     %4,%1\n"
+        "       stl_c   %1,%2\n"
+        "       beq     %1,1b\n"
+        "       mb\n"
+        "2:"
+        : "=&r" (prev), 
+          "=&r" (result)
+        : "m" (*atomic),
+          "Ir" ((gint64)oldval),
+          "Ir" (newval)
+        : "memory");
+  return result != 0;
+}
+#     elif GLIB_SIZEOF_VOID_P == 8 /* 64-bit system */
+static inline gboolean
+g_atomic_pointer_compare_and_exchange (gpointer *atomic, 
+				       gpointer  oldval, 
+				       gpointer  newval)
+{
+  gint32 result;
+  gpointer prev;
+  __asm__ __volatile__ (
+        "       mb\n"
+        "1:     ldq_l   %0,%2\n"
+        "       cmpeq   %0,%3,%1\n"
+        "       beq     %1,2f\n"
+        "       mov     %4,%1\n"
+        "       stq_c   %1,%2\n"
+        "       beq     %1,1b\n"
+        "       mb\n"
+        "2:"
+        : "=&r" (prev), 
+          "=&r" (result)
+        : "m" (*atomic),
+          "Ir" ((gint64)oldval),
+          "Ir" (newval)
+        : "memory");
+  return result != 0;
+}
+#     else /* What's that */
+#       error "Your system has an unsupported pointer size"
+#     endif /* GLIB_SIZEOF_VOID_P */
+static inline gint32
+g_atomic_int_exchange_and_add (gint32 *atomic, 
+			       gint32 val)
+{
+  gint32 result;
+  do
+    result = *atomic;
+  while (!g_atomic_int_compare_and_exchange (atomic, result, result + val));
+
+  return result;
+}
+ 
+static inline void
+g_atomic_int_add (gint32 *atomic, 
+		  gint32 val)
+{
+  g_atomic_int_exchange_and_add (atomic, val);
+}
+
+#      define G_ATOMIC_MEMORY_BARRIER() __asm ("mb" : : : "memory")
+
+#   elif defined(G_ATOMIC_INLINED_IMPLEMENTATION_X86_64)
+/* Adapted from CVS version 1.9 of glibc's sysdeps/x86_64/bits/atomic.h 
+ */
+static inline gint32
+g_atomic_int_exchange_and_add (gint32 *atomic, 
+			       gint32 val)
+{
+  gint32 result;
+
+  __asm__ __volatile__ ("lock; xaddl %0,%1"
+                        : "=r" (result), "=m" (*atomic) 
+			: "0" (val), "m" (*atomic));
+  return result;
+}
+ 
+static inline void
+g_atomic_int_add (gint32 *atomic, 
+		  gint32 val)
+{
+  __asm__ __volatile__ ("lock; addl %1,%0"
+			: "=m" (*atomic) 
+			: "ir" (val), "m" (*atomic));
+}
+
+static inline gboolean
+g_atomic_int_compare_and_exchange (gint32 *atomic, 
+				   gint32 oldval, 
+				   gint32 newval)
+{
+  gint32 result;
+ 
+  __asm __volatile ("lock; cmpxchgl %2, %1"
+		    : "=a" (result), "=m" (*atomic)
+		    : "r" (newval), "m" (*atomic), "0" (oldval)); 
+
+  return result == oldval;
+}
+
+static inline gboolean
+g_atomic_pointer_compare_and_exchange (gpointer *atomic, 
+				   gpointer  oldval, 
+				   gpointer  newval)
+{
+  gpointer result;
+ 
+  __asm __volatile ("lock; cmpxchgq %q2, %1"
+		    : "=a" (result), "=m" (*atomic)
+		    : "r" (newval), "m" (*atomic), "0" (oldval)); 
+
+  return result == oldval;
+}
+
+#     define  G_ATOMIC_MEMORY_BARRIER() /* Not needed */
+
+#   elif defined(G_ATOMIC_INLINED_IMPLEMENTATION_POWERPC)
+/* Adapted from CVS version 1.12 of glibc's sysdeps/powerpc/bits/atomic.h 
+ * and CVS version 1.3 of glibc's sysdeps/powerpc/powerpc32/bits/atomic.h 
+ * and CVS version 1.2 of glibc's sysdeps/powerpc/powerpc64/bits/atomic.h 
+ */
+static inline gint32
+g_atomic_int_exchange_and_add (gint32 *atomic, 
+			  gint32 val)
+{
+  gint32 result, temp;
+  __asm __volatile ("1:       lwarx   %0,0,%3\n"
+		    "         add     %1,%0,%4\n"
+		    "         stwcx.  %1,0,%3\n"
+		    "         bne-    1b"
+		    : "=&b" (result), "=&r" (temp), "=m" (*atomic)
+		    : "b" (atomic), "r" (val), "2" (*atomic)
+		    : "cr0", "memory");
+  return result;
+}
+ 
+static inline void
+g_atomic_int_add (gint32 *atomic, 
+		  gint32 val)
+{
+  g_atomic_int_exchange_and_add (atomic, val);
+}
+
+#     if GLIB_SIZEOF_VOID_P == 4 /* 32-bit system */
+static inline gboolean
+g_atomic_int_compare_and_exchange (gint32 *atomic, 
+			       gint32 oldval, 
+			       gint32 newval)
+{
+  gint32 result;
+  __asm __volatile ("sync\n"
+                    "1: lwarx   %0,0,%1\n"
+                    "   subf.   %0,%2,%0\n"
+                    "   bne     2f\n"
+                    "   stwcx.  %3,0,%1\n"
+                    "   bne-    1b\n"
+                    "2: isync"
+                    : "=&r" (result)
+                    : "b" (atomic), "r" (oldval), "r" (newval)
+                    : "cr0", "memory"); 
+  return result == 0;
+}
+
+static inline gboolean
+g_atomic_pointer_compare_and_exchange (gpointer *atomic, 
+				   gpointer  oldval, 
+				   gpointer  newval)
+{
+  gpointer result;
+  __asm __volatile ("sync\n"
+                    "1: lwarx   %0,0,%1\n"
+                    "   subf.   %0,%2,%0\n"
+                    "   bne     2f\n"
+                    "   stwcx.  %3,0,%1\n"
+                    "   bne-    1b\n"
+                    "2: isync"
+                    : "=&r" (result)
+                    : "b" (atomic), "r" (oldval), "r" (newval)
+                    : "cr0", "memory"); 
+  return result == 0;
+}
+#     elif GLIB_SIZEOF_VOID_P == 8 /* 64-bit system */
+static inline gboolean
+g_atomic_int_compare_and_exchange (gint32 *atomic, 
+			       gint32 oldval, 
+			       gint32 newval)
+{
+  __asm __volatile ("sync\n"
+                    "1: lwarx   %0,0,%1\n"
+                    "   extsw   %0,%0\n"
+                    "   subf.   %0,%2,%0\n"
+                    "   bne     2f\n"
+                    "   stwcx.  %3,0,%1\n"
+                    "   bne-    1b\n"
+                    "2: isync"
+                    : "=&r" (result)
+                    : "b" (atomic), "r" (oldval), "r" (newval)
+                    : "cr0", "memory"); 
+  return result == 0;
+}
+
+static inline gboolean
+g_atomic_pointer_compare_and_exchange (gpointer *atomic, 
+				   gpointer  oldval, 
+				   gpointer  newval)
+{
+  gpointer result;
+  __asm __volatile ("sync\n"
+		    "1: ldarx   %0,0,%1\n"
+                    "   subf.   %0,%2,%0\n"
+                    "   bne     2f\n"
+                    "   stdcx.  %3,0,%1\n"
+                    "   bne-    1b\n"
+                    "2: isync"
+                    : "=&r" (result)
+                    : "b" (atomic), "r" (oldval), "r" (newval)
+                    : "cr0", "memory"); 
+  return result == 0;
+}
+#     else /* What's that */
+#       error "Your system has an unsupported pointer size"
+#     endif /* GLIB_SIZEOF_VOID_P */
+
+#     define  G_ATOMIC_MEMORY_BARRIER() __asm ("sync" : : : "memory")
+
+#   elif defined(G_ATOMIC_INLINED_IMPLEMENTATION_IA64)
+/* Adapted from CVS version 1.8 of glibc's sysdeps/ia64/bits/atomic.h
+ */
+static inline gint32
+g_atomic_int_exchange_and_add (gint32 *atomic, 
+			  gint32 val)
+{
+  return __sync_fetch_and_add_si (atomic, val);
+}
+ 
+static inline void
+g_atomic_int_add (gint32 *atomic, 
+		  gint32 val)
+{
+  __sync_fetch_and_add_si (atomic, val);
+}
+
+static inline gboolean
+g_atomic_int_compare_and_exchange (gint32 *atomic, 
+			       gint32 oldval, 
+			       gint32 newval)
+{
+  return __sync_bool_compare_and_exchange_si (atomic, oldval, newval);
+}
+
+static inline gboolean
+g_atomic_pointer_compare_and_exchange (gpointer *atomic, 
+				   gpointer  oldval, 
+				   gpointer  newval)
+{
+  return __sync_bool_compare_and_exchange_di ((long *)atomic, 
+					  (long)oldval, (long)newval);
+}
+
+#     define  G_ATOMIC_MEMORY_BARRIER() __sync_synchronize ()
+
+#   else /* !G_ATOMIC_INLINED_IMPLEMENTATION_... */
+#     define G_ATOMIC_USE_FALLBACK_IMPLEMENTATION
+#   endif /* G_ATOMIC_INLINED_IMPLEMENTATION_... */
+# else /* !__GNU__ */
+#   define G_ATOMIC_USE_FALLBACK_IMPLEMENTATION
+# endif /* __GNUC__ */
+#else /* !G_THREADS_ENABLED */
+gint32 g_atomic_int_exchange_and_add (gint32 *atomic, gint32  val);
+# define g_atomic_int_add(atomic, val) (void)(*(atomic) += (val))
+# define g_atomic_int_compare_and_exchange(atomic, oldval, newval)		\
+  (*(atomic) == (oldval) ? (*(atomic) = (newval), TRUE) : FALSE)
+# define g_atomic_pointer_compare_and_exchange(atomic, oldval, newval)	\
+  (*(atomic) == (oldval) ? (*(atomic) = (newval), TRUE) : FALSE)
+# define g_atomic_int_get(atomic) (*(atomic))
+# define g_atomic_pointer_get(atomic) (*(atomic))
+#endif /* G_THREADS_ENABLED */
+
+#ifdef G_ATOMIC_USE_FALLBACK_IMPLEMENTATION
+# define g_atomic_int_exchange_and_add					\
+    g_atomic_int_exchange_and_add_fallback
+# define g_atomic_int_add						\
+    g_atomic_int_add_fallback
+# define g_atomic_int_compare_and_exchange					\
+    g_atomic_int_compare_and_exchange_fallback
+# define g_atomic_pointer_compare_and_exchange 				\
+    g_atomic_pointer_compare_and_exchange_fallback
+# define g_atomic_int_get 						\
+    g_atomic_int_get_fallback
+# define g_atomic_pointer_get 						\
+    g_atomic_pointer_get_fallback
+#else /* !G_ATOMIC_USE_FALLBACK_IMPLEMENTATION */
+static inline gint32
+g_atomic_int_get (gint32 *atomic)
+{
+  gint32 result = *atomic;
+  G_ATOMIC_MEMORY_BARRIER ();
+  return result;
+}
+
+static inline gpointer
+g_atomic_pointer_get (gpointer *atomic)
+{
+  gpointer result = *atomic;
+  G_ATOMIC_MEMORY_BARRIER ();
+  return result;
+}   
+#endif /* G_ATOMIC_USE_FALLBACK_IMPLEMENTATION */
+
+#define g_atomic_int_inc(atomic) (g_atomic_int_add ((atomic), 1))
+#define g_atomic_int_dec_and_test(atomic)				\
+  (g_atomic_int_exchange_and_add ((atomic), -1) == 1)
+
+G_END_DECLS
+ 
+#endif /* __G_ATOMIC_H__ */