MIPS specific atomicity functions.

2024-11-26 15:00:06 +00:00 · 2001-05-27 08:41:04 +00:00 · 2001-05-27 08:41:04 +00:00 · 3a97df5aa5
commit 3a97df5aa5
parent b81e88a055
1 changed files with 128 additions and 0 deletions
--- a/sysdeps/mips/atomicity.h
+++ b/sysdeps/mips/atomicity.h
@ -0,0 +1,128 @@
+/* Low-level functions for atomic operations. Mips version.
+
+   Copyright (C) 2001 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 _MIPS_ATOMICITY_H
+#define _MIPS_ATOMICITY_H    1
+
+#include <sgidefs.h>
+#include <inttypes.h>
+
+#if (_MIPS_ISA >= _MIPS_ISA_MIPS2)
+
+static inline int
+__attribute__ ((unused))
+exchange_and_add (volatile uint32_t *mem, int val)
+{
+  int result, tmp;
+
+  __asm__ __volatile__
+    ("/* Inline exchange & add */\n\t"
+     "1:\n\t"
+     "ll	%0,%3\n\t"
+     "addu	%1,%4,%0\n\t"
+     "sc	%1,%2\n\t"
+     "beqz	%1,1b\n\t"
+     "/* End exchange & add */"
+     : "=&r"(result), "=&r"(tmp), "=m"(*mem)
+     : "m" (*mem), "r"(val)
+     : "memory");
+
+  return result;
+}
+
+static inline void
+__attribute__ ((unused))
+atomic_add (volatile uint32_t *mem, int val)
+{
+  int result;
+
+  __asm__ __volatile__
+    ("/* Inline atomic add */\n\t"
+     "1:\n\t"
+     "ll	%0,%2\n\t"
+     "addu	%0,%3,%0\n\t"
+     "sc	%0,%1\n\t"
+     "beqz	%0,1b\n\t"
+     "/* End atomic add */"
+     : "=&r"(result), "=m"(*mem)
+     : "m" (*mem), "r"(val)
+     : "memory");
+}
+
+static inline int
+__attribute__ ((unused))
+compare_and_swap (volatile long int *p, long int oldval, long int newval)
+{
+  long int ret;
+
+  __asm__ __volatile__
+    ("/* Inline compare & swap */\n\t"
+     "1:\n\t"
+     "ll	%0,%4\n\t"
+     ".set	push\n"
+     ".set	noreorder\n\t"
+     "bne	%0,%2,2f\n\t"
+     "move	%0,%3\n\t"
+     ".set	pop\n\t"
+     "sc	%0,%1\n\t"
+     "beqz	%0,1b\n"
+     "2:\n\t"
+     "/* End compare & swap */"
+     : "=&r" (ret), "=m" (*p)
+     : "r" (oldval), "r" (newval), "m" (*p)
+     : "memory");
+
+  return ret;
+}
+
+#else /* (_MIPS_ISA >= _MIPS_ISA_MIPS2) */
+
+#warning MIPS I atomicity functions are not atomic
+
+static inline int
+__attribute__ ((unused))
+exchange_and_add (volatile uint32_t *mem, int val)
+{
+  int result = *mem;
+  *mem += val;
+  return result;
+}
+
+static inline void
+__attribute__ ((unused))
+atomic_add (volatile uint32_t *mem, int val)
+{
+  *mem += val;
+}
+
+static inline int
+__attribute__ ((unused))
+compare_and_swap (volatile long int *p, long int oldval, long int newval)
+{
+  if (*p != oldval)
+    return 0;
+
+  *p = newval;
+  return 1;
+}
+
+#endif /* !(_MIPS_ISA >= _MIPS_ISA_MIPS2) */
+
+#endif /* atomicity.h */