LXR linux/arch/nios2/include/asm/switch

   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 */
  32