1  /* CPU strand yielding for busy loops.  Linux/sparc version.
       2     Copyright (C) 2017-2023 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  #include <sparc-ifunc.h>
      20  
      21  #ifdef __sparc_v9__
      22  static void
      23  __cpu_relax_generic (void)
      24  {
      25    asm volatile ("rd %ccr, %g0;"
      26  		"rd %ccr, %g0;"
      27  		"rd %ccr, %g0");
      28  }
      29  
      30  static void
      31  __cpu_relax_pause (void)
      32  {
      33    asm volatile ("wr %g0, 128, %asr27");
      34  }
      35  
      36  sparc_libc_ifunc (__cpu_relax,
      37  		  hwcap & HWCAP_SPARC_PAUSE
      38  		  ? __cpu_relax_pause
      39  		  : __cpu_relax_generic)
      40  #endif