1 #ifndef _H8300_SWITCH_TO_H
2 #define _H8300_SWITCH_TO_H
5 * switch_to(n) should switch tasks to task ptr, first checking that
6 * ptr isn't the current task, in which case it does nothing. This
7 * also clears the TS-flag if the task we switched to has used the
8 * math co-processor latest.
11 * switch_to() saves the extra registers, that are not saved
12 * automatically by SAVE_SWITCH_STACK in resume(), ie. d0-d5 and
13 * a0-a1. Some of these are used by schedule() and its predecessors
14 * and so we might get see unexpected behaviors when a task returns
15 * with unexpected register values.
17 * syscall stores these registers itself and none of them are used
18 * by syscall after the function in the syscall has been called.
20 * Beware that resume now expects *next to be in d1 and the offset of
21 * tss to be in a1. This saves a few instructions as we no longer have
22 * to push them onto the stack and read them back right after.
24 * 02/17/96 - Jes Sorensen (jds@kom.auc.dk)
26 * Changed 96/09/19 by Andreas Schwab
27 * pass prev in a0, next in a1, offset of tss in d1, and whether
28 * the mm structures are shared in d2 (to avoid atc flushing).
30 * H8/300 Porting 2002/09/04 Yoshinori Sato
33 asmlinkage void resume(void);
34 #define switch_to(prev, next, last) \
37 __asm__ __volatile__( \
44 : "r" (&(prev->thread)), \
45 "r" (&(next->thread)), \
47 : "cc", "er0", "er1", "er2", "er3"); \
51 #endif /* _H8300_SWITCH_TO_H */