1  /* Low-level functions for atomic operations. Nios II version.
       2     Copyright (C) 2012-2023 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 Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the 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     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library.  If not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #ifndef _NIOS2_ATOMIC_MACHINE_H
      20  #define _NIOS2_ATOMIC_MACHINE_H 1
      21  
      22  #define __HAVE_64B_ATOMICS 0
      23  #define USE_ATOMIC_COMPILER_BUILTINS 0
      24  
      25  /* XXX Is this actually correct?  */
      26  #define ATOMIC_EXCHANGE_USES_CAS 1
      27  
      28  #define __arch_compare_and_exchange_val_8_acq(mem, newval, oldval)	\
      29    (abort (), (__typeof (*mem)) 0)
      30  #define __arch_compare_and_exchange_val_16_acq(mem, newval, oldval)	\
      31    (abort (), (__typeof (*mem)) 0)
      32  #define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval)	\
      33    (abort (), (__typeof (*mem)) 0)
      34  
      35  #define __arch_compare_and_exchange_bool_8_acq(mem, newval, oldval)	\
      36    (abort (), 0)
      37  #define __arch_compare_and_exchange_bool_16_acq(mem, newval, oldval)	\
      38    (abort (), 0)
      39  #define __arch_compare_and_exchange_bool_64_acq(mem, newval, oldval)	\
      40    (abort (), 0)
      41  
      42  #define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval)	\
      43    ({									\
      44       register int r2 asm ("r2");					\
      45       register int* r4 asm ("r4") = (int*)(mem);				\
      46       register int r5 asm ("r5");					\
      47       register int r6 asm ("r6") = (int)(newval);			\
      48       int retval, orig_oldval = (int)(oldval);				\
      49       long kernel_cmpxchg = 0x1004;					\
      50       while (1)								\
      51         {								\
      52           r5 = *r4;							\
      53  	 if (r5 != orig_oldval)						\
      54  	   {								\
      55  	     retval = r5;						\
      56  	     break;							\
      57  	   }								\
      58  	 asm volatile ("callr %1\n"					\
      59  		       : "=r" (r2)					\
      60  		       : "r" (kernel_cmpxchg), "r" (r4), "r" (r5), "r" (r6) \
      61  		       : "ra", "memory");				\
      62  	 if (!r2) { retval = orig_oldval; break; }			\
      63         }								\
      64       (__typeof (*(mem))) retval;					\
      65    })
      66  
      67  #define __arch_compare_and_exchange_bool_32_acq(mem, newval, oldval)	\
      68    ({									\
      69       register int r2 asm ("r2");					\
      70       register int *r4 asm ("r4") = (int*)(mem);				\
      71       register int r5 asm ("r5") = (int)(oldval);			\
      72       register int r6 asm ("r6") = (int)(newval);			\
      73       long kernel_cmpxchg = 0x1004;					\
      74       asm volatile ("callr %1\n"						\
      75  		   : "=r" (r2)						\
      76  		   : "r" (kernel_cmpxchg), "r" (r4), "r" (r5), "r" (r6) \
      77  		   : "ra", "memory");					\
      78       r2;								\
      79    })
      80  
      81  #define atomic_full_barrier()  ({ asm volatile ("sync"); })
      82  
      83  #endif /* _NIOS2_ATOMIC_MACHINE_H */