[linuxsh-dev] switch_to

[NIIBE Y. <gn...@m1...>]

NIIBE Yutaka wrote:
 > Index: include/asm-sh/system.h
 > ===================================================================
 > RCS file: /cvsroot/linuxsh/linux/include/asm-sh/system.h,v
 > retrieving revision 1.1.1.1
 > diff -u -3 -p -r1.1.1.1 system.h
 > --- include/asm-sh/system.h	15 Oct 2001 20:45:11 -0000	1.1.1.1
 > +++ include/asm-sh/system.h	22 Mar 2002 01:57:26 -0000
 > @@ -20,8 +20,7 @@ typedef struct {
 >  #error no SMP SuperH
 >  #else
 >  #define prepare_to_switch()	do { } while(0)
 > -#define switch_to(prev,next,last) do { \
 > - register struct task_struct *__last; \
 > +#define switch_to(prev, next) do { \
 >   register unsigned long *__ts1 __asm__ ("r1") = &prev->thread.sp; \
 >   register unsigned long *__ts2 __asm__ ("r2") = &prev->thread.pc; \
 >   register unsigned long *__ts4 __asm__ ("r4") = (unsigned long *)prev; \
 > @@ -40,7 +39,6 @@ typedef struct {
 >  		       "mov.l	r14, @-r15\n\t" \
 >  		       "mov.l	r15, @r1	! save SP\n\t" \
 >  		       "mov.l	@r6, r15	! change to new stack\n\t" \
 > -		       "mov.l	%0, @-r15	! push R0 onto new stack\n\t" \
 >  		       "mova	1f, %0\n\t" \
 >  		       "mov.l	%0, @r2	! save PC\n\t" \
 >  		       "mov.l	2f, %0\n\t" \
 > @@ -50,7 +48,6 @@ typedef struct {
 >  		       "2:\n\t" \
 >  		       ".long	" "__switch_to\n" \
 >  		       "1:\n\t" \
 > -		       "mov.l	@r15+, %0	! pop R0 from new stack\n\t" \
 >  		       "mov.l	@r15+, r14\n\t" \
 >  		       "mov.l	@r15+, r13\n\t" \
 >  		       "mov.l	@r15+, r12\n\t" \
 > @@ -60,12 +57,11 @@ typedef struct {
 >  		       "mov.l	@r15+, r8\n\t" \
 >  		       "lds.l	@r15+, pr\n\t" \
 >  		       "ldc.l	@r15+, gbr\n\t" \
 > -		       :"=&z" (__last) \
 > -		       :"0" (prev), \
 > -			"r" (__ts1), "r" (__ts2), \
 > -			"r" (__ts4), "r" (__ts5), "r" (__ts6), "r" (__ts7) \
 > -		       :"r3", "t"); \
 > -  last = __last; \
 > +		       : /* No output */ \
 > +		       : "r" (prev), \
			  z
This should be "z" so that we can use "mova" instruction (only r0 is allowed).

 > +			 "r" (__ts1), "r" (__ts2), \
 > +			 "r" (__ts4), "r" (__ts5), "r" (__ts6), "r" (__ts7) \
 > +		       : "r3", "t"); \
 >  } while (0)
 >  #endif
--