Disintegrate asm/system.h for H8300
Disintegrate asm/system.h for H8300.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Yoshinori Sato <ysato@users.sourceforge.jp>
diff --git a/arch/h8300/include/asm/switch_to.h b/arch/h8300/include/asm/switch_to.h
new file mode 100644
index 0000000..cdd8731
--- /dev/null
+++ b/arch/h8300/include/asm/switch_to.h
@@ -0,0 +1,50 @@
+#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 */