| #ifndef _H8300_SWITCH_TO_H |
| #define _H8300_SWITCH_TO_H |
| |
| /* |
| * switch_to(n) should switch tasks to task ptr, first checking that |
| * ptr isn't the current task, in which case it does nothing. This |
| * also clears the TS-flag if the task we switched to has used the |
| * math co-processor latest. |
| */ |
| /* |
| * switch_to() saves the extra registers, that are not saved |
| * automatically by SAVE_SWITCH_STACK in resume(), ie. d0-d5 and |
| * a0-a1. Some of these are used by schedule() and its predecessors |
| * and so we might get see unexpected behaviors when a task returns |
| * with unexpected register values. |
| * |
| * syscall stores these registers itself and none of them are used |
| * by syscall after the function in the syscall has been called. |
| * |
| * Beware that resume now expects *next to be in d1 and the offset of |
| * tss to be in a1. This saves a few instructions as we no longer have |
| * to push them onto the stack and read them back right after. |
| * |
| * 02/17/96 - Jes Sorensen (jds@kom.auc.dk) |
| * |
| * Changed 96/09/19 by Andreas Schwab |
| * pass prev in a0, next in a1, offset of tss in d1, and whether |
| * the mm structures are shared in d2 (to avoid atc flushing). |
| * |
| * H8/300 Porting 2002/09/04 Yoshinori Sato |
| */ |
| |
| asmlinkage void resume(void); |
| #define switch_to(prev,next,last) { \ |
| void *_last; \ |
| __asm__ __volatile__( \ |
| "mov.l %1, er0\n\t" \ |
| "mov.l %2, er1\n\t" \ |
| "mov.l %3, er2\n\t" \ |
| "jsr @_resume\n\t" \ |
| "mov.l er2,%0\n\t" \ |
| : "=r" (_last) \ |
| : "r" (&(prev->thread)), \ |
| "r" (&(next->thread)), \ |
| "g" (prev) \ |
| : "cc", "er0", "er1", "er2", "er3"); \ |
| (last) = _last; \ |
| } |
| |
| #endif /* _H8300_SWITCH_TO_H */ |
