From: Frank van Maarseveen <frankvm@frankvm.com>
To: linuxppc-dev@ozlabs.org
Subject: include/asm-ppc/atomic.h: fluff in inline assembly code?
Date: Wed, 29 Jun 2005 16:50:13 +0200 [thread overview]
Message-ID: <20050629145013.GA21494@janus> (raw)
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
next reply other threads:[~2005-06-29 16:01 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-06-29 14:50 Frank van Maarseveen [this message]
2005-06-29 16:14 ` include/asm-ppc/atomic.h: fluff in inline assembly code? Andreas Schwab
2005-06-29 18:36 ` Frank van Maarseveen
2005-06-29 22:34 ` Andreas Schwab
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