Atomic operations for Arm.

1 files changed, 86 insertions, 0 deletions

diff --git a/sysdeps/arm/atomicity.h b/sysdeps/arm/atomicity.h
new file mode 100644
index 0000000..01bd64e
--- /dev/null
+++ b/sysdeps/arm/atomicity.h
@@ -0,0 +1,86 @@
+/* Low-level functions for atomic operations.  ARM version.
+   Copyright (C) 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
+   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)
+{
+  int tmp1;
+  int tmp2;
+  int result;
+  __asm__ ("\n"
+	   "0:\tldr\t%0,[%3]\n\t"
+	   "add\t%1,%0,%4\n\t"
+	   "swp\t%2,%1,[%3]\n\t"
+	   "cmp\t%0,%2\n\t"
+	   "swpne\t%1,%2,[%3]\n\t"
+	   "bne\t0b"
+	   : "=&r" (result), "=&r" (tmp1), "=&r" (tmp2)
+	   : "r" (mem), "r"(val)
+	   : "cc", "memory");
+  return result;
+}
+
+static inline void
+__attribute__ ((unused))
+atomic_add (volatile uint32_t *mem, int val)
+{
+  int tmp1;
+  int tmp2;
+  int tmp3;
+  __asm__ ("\n"
+	   "0:\tldr\t%0,[%3]\n\t"
+	   "add\t%1,%0,%4\n\t"
+	   "swp\t%2,%1,[%3]\n\t"
+	   "cmp\t%0,%2\n\t"
+	   "swpne\t%1,%2,[%3]\n\t"
+	   "bne\t0b"
+	   : "=&r" (tmp1), "=&r" (tmp2), "=&r" (tmp3)
+	   : "r" (mem), "r"(val)
+	   : "cc", "memory");
+}
+
+static inline int
+__attribute__ ((unused))
+compare_and_swap (volatile long int *p, long int oldval, long int newval)
+{
+  int result, tmp;
+  __asm__ ("\n"
+	   "0:\tldr\t%1,[%2]\n\t"
+	   "mov\t%0,#0\n\t"
+	   "cmp\t%1,%4\n\t"
+	   "bne\t1f\n\t"
+	   "swp\t%0,%3,[%2]\n\t"
+	   "cmp\t%1,%0\n\t"
+	   "swpne\t%1,%0,[%2]\n\t"
+	   "bne\t0b\n\t"
+	   "mov\t%0,#1\n"
+	   "1:"
+	   : "=&r" (result), "=&r" (tmp)
+	   : "r" (p), "r" (newval), "r" (oldval)
+	   : "cc", "memory");
+}
+
+#endif /* atomicity.h */