1/* AMD GCN atomic operations
2   Copyright (C) 2020 Free Software Foundation, Inc.
3   Contributed by Mentor Graphics.
4
5   This file is free software; you can redistribute it and/or modify it
6   under the terms of the GNU General Public License as published by the
7   Free Software Foundation; either version 3, or (at your option) any
8   later version.
9
10   This file is distributed in the hope that it will be useful, but
11   WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   General Public License for more details.
14
15   Under Section 7 of GPL version 3, you are granted additional
16   permissions described in the GCC Runtime Library Exception, version
17   3.1, as published by the Free Software Foundation.
18
19   You should have received a copy of the GNU General Public License and
20   a copy of the GCC Runtime Library Exception along with this program;
21   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
22   <http://www.gnu.org/licenses/>.  */
23
24#include <stdbool.h>
25
26#define __SYNC_SUBWORD_COMPARE_AND_SWAP(TYPE, SIZE)			     \
27									     \
28TYPE									     \
29__sync_val_compare_and_swap_##SIZE (TYPE *ptr, TYPE oldval, TYPE newval)     \
30{									     \
31  unsigned int *wordptr = (unsigned int *)((__UINTPTR_TYPE__ ) ptr & ~3UL);  \
32  int shift = ((__UINTPTR_TYPE__ ) ptr & 3UL) * 8;			     \
33  unsigned int valmask = (1 << (SIZE * 8)) - 1;				     \
34  unsigned int wordmask = ~(valmask << shift);				     \
35  unsigned int oldword = *wordptr;					     \
36  for (;;)								     \
37    {									     \
38      TYPE prevval = (oldword >> shift) & valmask;			     \
39      if (__builtin_expect (prevval != oldval, 0))			     \
40	return prevval;							     \
41      unsigned int newword = oldword & wordmask;			     \
42      newword |= ((unsigned int) newval) << shift;			     \
43      unsigned int prevword						     \
44	  = __sync_val_compare_and_swap_4 (wordptr, oldword, newword);	     \
45      if (__builtin_expect (prevword == oldword, 1))			     \
46	return oldval;							     \
47      oldword = prevword;						     \
48    }									     \
49}									     \
50									     \
51bool									     \
52__sync_bool_compare_and_swap_##SIZE (TYPE *ptr, TYPE oldval, TYPE newval)    \
53{									     \
54  return __sync_val_compare_and_swap_##SIZE (ptr, oldval, newval) == oldval; \
55}
56
57__SYNC_SUBWORD_COMPARE_AND_SWAP (unsigned char, 1)
58__SYNC_SUBWORD_COMPARE_AND_SWAP (unsigned short, 2)
59
60