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-rw-r--r--libc/sysdeps/linux/arm/bits/atomicity.h87
1 files changed, 87 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/arm/bits/atomicity.h b/libc/sysdeps/linux/arm/bits/atomicity.h
new file mode 100644
index 000000000..1a437a6d3
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+++ b/libc/sysdeps/linux/arm/bits/atomicity.h
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+/* 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 Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; 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");
+ return result;
+}
+
+#endif /* atomicity.h */