Low-level atomicity functions for m68k.

sysdeps/m68k/m68020/atomicity.h

@@ -0,0 +1,65 @@
+/* Low-level functions for atomic operations.  m680x0 version, x >= 2.
+   Copyright (C) 1997 Free Software Foundation, Inc.
+   Contributed by Andreas Schwab <schwab@issan.informatik.uni-dortmund.de>.
+
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#ifndef _ATOMICITY_H
+#define _ATOMICITY_H	1
+
+#include <inttypes.h>
+
+
+static inline int
+__attribute__ ((unused))
+exchange_and_add (volatile uint32_t *mem, int val)
+{
+  register int result = *mem;
+  register int temp;
+  __asm__ __volatile__ ("1: move%.l %0,%1;"
+			"   add%.l %2,%1;"
+			"   cas%.l %0,%1,%3;"
+			"   jbne 1b"
+			: "=d" (result), "=&d" (temp)
+			: "d" (val), "m" (*mem), "0" (result) : "memory");
+  return result;
+}
+
+static inline void
+__attribute__ ((unused))
+atomic_add (volatile uint32_t *mem, int val)
+{
+  /* XXX Use cas here as well?  */
+  __asm__ __volatile__ ("add%.l %0,%1"
+			: : "ir" (val), "m" (*mem) : "memory");
+}
+
+static inline int
+__attribute__ ((unused))
+compare_and_swap (volatile long int *p, long int oldval, long int newval)
+{
+  char ret;
+  long int readval;
+
+  __asm__ __volatile__ ("cas%.l %2,%3,%1; seq %0"
+                        : "=dm" (ret), "=m" (*p), "=d" (readval)
+                        : "d" (newval), "m" (*p), "2" (oldval));
+  return ret;
+}
+
+#endif /* atomicity.h */