libstdc++-v3/config/cpu/arm/atomicity.h

   1 /* Low-level functions for atomic operations.  ARM version.
   2    Copyright (C) 2000 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #ifndef _ATOMICITY_H
  21 #define _ATOMICITY_H    1
  22
  23 #ifdef _GLIBCPP_HAVE_INTTYPES_H
  24 #include <inttypes.h>
  25 #else
  26 typedef unsigned int    uint32_t;
  27 typedef int             int32_t;
  28 #endif
  29
  30 static inline int
  31 __attribute__ ((unused))
  32 exchange_and_add (volatile uint32_t *mem, int val)
  33 {
  34   int tmp, tmp2, result;
  35   __asm__ ("\
  36 0:      ldr     %0,[%3]
  37         add     %1,%0,%4
  38         swp     %2,%1,[%3]
  39         cmp     %0,%2
  40         swpne   %1,%2,[%3]
  41         bne     0b
  42 " : "=&r"(result), "=&r"(tmp), "=&r"(tmp2) : "r" (mem), "r"(val) : "cc", "memory");
  43   return result;
  44 }
  45
  46 static inline void
  47 __attribute__ ((unused))
  48 atomic_add (volatile uint32_t *mem, int val)
  49 {
  50   int tmp, tmp2, tmp3;
  51   __asm__ ("\
  52 0:      ldr     %0,[%3]
  53         add     %1,%0,%4
  54         swp     %2,%1,[%3]
  55         cmp     %0,%2
  56         swpne   %1,%2,[%3]
  57         bne     0b
  58 " : "=&r"(tmp), "=&r"(tmp2), "=&r"(tmp3) : "r" (mem), "r"(val) : "cc", "memory");
  59 }
  60
  61 static inline int
  62 __attribute__ ((unused))
  63 compare_and_swap (volatile long int *p, long int oldval, long int newval)
  64 {
  65   int result, tmp;
  66   __asm__ ("\
  67 0:      ldr     %1,[%2]
  68         mov     %0,#0
  69         cmp     %1,%4
  70         bne     1f
  71         swp     %0,%3,[%2]
  72         cmp     %1,%0
  73         swpne   %1,%0,[%2]
  74         bne     0b
  75         mov     %0,#1
  76 1:
  77 " : "=&r"(result), "=&r"(tmp) : "r" (p), "r" (newval), "r" (oldval) : "cc", "memory");
  78 }
  79
  80 static inline long int
  81 __attribute__ ((unused))
  82 always_swap (volatile long int *p, long int newval)
  83 {
  84   long int result;
  85   __asm__ ("\
  86         swp     %0,%2,[%1]
  87 " : "=&r"(result) : "r"(p), "r"(newval) : "memory");
  88   return result;
  89 }
  90
  91 static inline int
  92 __attribute__ ((unused))
  93 test_and_set (volatile long int *p, long int newval)
  94 {
  95   int result, tmp, tmp2, tmp3;
  96   __asm__ ("\
  97 0:      ldr     %0,[%2]
  98         cmp     %0,#0
  99         bne     1f
 100         swp     %1,%3,[%2]
 101         cmp     %0,%1
 102         swpne   %0,%1,[%2]
 103         bne     0b
 104 1:
 105 " : "=&r"(result), "=r" (tmp) : "r"(p), "r"(newval) : "cc", "memory");
 106   return result;
 107 }
 108
 109 #endif /* atomicity.h */