arch/m32r/include/asm/switch_to.h

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2001  Hiroyuki Kondo, Hirokazu Takata, and Hitoshi Yamamoto
   7  * Copyright (C) 2004, 2006  Hirokazu Takata <takata at linux-m32r.org>
   8  */
   9 #ifndef _ASM_M32R_SWITCH_TO_H
  10 #define _ASM_M32R_SWITCH_TO_H
  11
  12 /*
  13  * switch_to(prev, next) should switch from task `prev' to `next'
  14  * `prev' will never be the same as `next'.
  15  *
  16  * `next' and `prev' should be struct task_struct, but it isn't always defined
  17  */
  18
  19 #if defined(CONFIG_FRAME_POINTER) || \
  20         !defined(CONFIG_SCHED_OMIT_FRAME_POINTER)
  21 #define M32R_PUSH_FP "  push fp\n"
  22 #define M32R_POP_FP  "  pop  fp\n"
  23 #else
  24 #define M32R_PUSH_FP ""
  25 #define M32R_POP_FP  ""
  26 #endif
  27
  28 #define switch_to(prev, next, last)  do { \
  29         __asm__ __volatile__ ( \
  30                 "       seth    lr, #high(1f)                           \n" \
  31                 "       or3     lr, lr, #low(1f)                        \n" \
  32                 "       st      lr, @%4  ; store old LR                 \n" \
  33                 "       ld      lr, @%5  ; load new LR                  \n" \
  34                         M32R_PUSH_FP \
  35                 "       st      sp, @%2  ; store old SP                 \n" \
  36                 "       ld      sp, @%3  ; load new SP                  \n" \
  37                 "       push    %1  ; store `prev' on new stack         \n" \
  38                 "       jmp     lr                                      \n" \
  39                 "       .fillinsn                                       \n" \
  40                 "1:                                                     \n" \
  41                 "       pop     %0  ; restore `__last' from new stack   \n" \
  42                         M32R_POP_FP \
  43                 : "=r" (last) \
  44                 : "0" (prev), \
  45                   "r" (&(prev->thread.sp)), "r" (&(next->thread.sp)), \
  46                   "r" (&(prev->thread.lr)), "r" (&(next->thread.lr)) \
  47                 : "memory", "lr" \
  48         ); \
  49 } while(0)
  50
  51 #endif /* _ASM_M32R_SWITCH_TO_H */