arch/nios2/include/asm/switch_to.h

   1 /*
   2  * Copyright (C) 2004 Microtronix Datacom Ltd.
   3  *
   4  * This file is subject to the terms and conditions of the GNU General Public
   5  * License. See the file "COPYING" in the main directory of this archive
   6  * for more details.
   7  */
   8 #ifndef _ASM_NIOS2_SWITCH_TO_H
   9 #define _ASM_NIOS2_SWITCH_TO_H
  10
  11 /*
  12  * switch_to(n) should switch tasks to task ptr, first checking that
  13  * ptr isn't the current task, in which case it does nothing.  This
  14  * also clears the TS-flag if the task we switched to has used the
  15  * math co-processor latest.
  16  */
  17 #define switch_to(prev, next, last)                     \
  18 {                                                       \
  19         void *_last;                                    \
  20         __asm__ __volatile__ (                          \
  21                 "mov    r4, %1\n"                       \
  22                 "mov    r5, %2\n"                       \
  23                 "call   resume\n"                       \
  24                 "mov    %0,r4\n"                        \
  25                 : "=r" (_last)                          \
  26                 : "r" (prev), "r" (next)                \
  27                 : "r4", "r5", "r7", "r8", "ra");        \
  28         (last) = _last;                                 \
  29 }
  30
  31 #endif /* _ASM_NIOS2_SWITCH_TO_H */