Subject: include/asm-ppc/atomic.h: fluff in inline assembly code?

From: Frank van Maarseveen <[email-masked]>
Date: Wed, 29 Jun 2005 16:50:13 +0200

Does anyone know why there are often excess arguments in asm() here?

For example,

	static __inline__ void atomic_add(int a, atomic_t *v)
	{
		int t;

		__asm__ __volatile__(
	"1:     lwarx   %0,0,%3         # atomic_add\n\
		add     %0,%2,%0\n"
		PPC405_ERR77(0,%3)
	"       stwcx.  %0,0,%3 \n\
		bne-    1b"
		: "=&r" (t), "=m" (v->counter)
		: "r" (a), "r" (&v->counter), "m" (v->counter)
		: "cc");
	}

seems equivalent to 

	static __inline__ void atomic_add(int a, atomic_t *v)
	{
		int t;

		__asm__ __volatile__(
	"1:     lwarx   %0,0,%2         # atomic_add\n\
		add     %0,%1,%0\n"
		PPC405_ERR77(0,%2)
	"       stwcx.  %0,0,%2 \n\
		bne-    1b"
		: "=&r" (t)
		: "r" (a), "r" (&v->counter)
		: "cc");
	}

What is the point of all those v->counter arguments?

-- 
Frank