atomic.h
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/*
* PowerPC64 atomic operations
*
* Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM
* Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _ASM_PPC64_ATOMIC_H_
#define _ASM_PPC64_ATOMIC_H_
#include <asm/memory.h>
typedef struct { volatile int counter; } atomic_t;
#define ATOMIC_INIT(i) { (i) }
#define atomic_read(v) ((v)->counter)
#define atomic_set(v,i) (((v)->counter) = (i))
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\
stwcx. %0,0,%3\n\
bne- 1b"
: "=&r" (t), "=m" (v->counter)
: "r" (a), "r" (&v->counter), "m" (v->counter)
: "cc");
}
static __inline__ int atomic_add_return(int a, atomic_t *v)
{
int t;
__asm__ __volatile__(
EIEIO_ON_SMP
"1: lwarx %0,0,%2 # atomic_add_return\n\
add %0,%1,%0\n\
stwcx. %0,0,%2\n\
bne- 1b"
ISYNC_ON_SMP
: "=&r" (t)
: "r" (a), "r" (&v->counter)
: "cc", "memory");
return t;
}
#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
static __inline__ void atomic_sub(int a, atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%3 # atomic_sub\n\
subf %0,%2,%0\n\
stwcx. %0,0,%3\n\
bne- 1b"
: "=&r" (t), "=m" (v->counter)
: "r" (a), "r" (&v->counter), "m" (v->counter)
: "cc");
}
static __inline__ int atomic_sub_return(int a, atomic_t *v)
{
int t;
__asm__ __volatile__(
EIEIO_ON_SMP
"1: lwarx %0,0,%2 # atomic_sub_return\n\
subf %0,%1,%0\n\
stwcx. %0,0,%2\n\
bne- 1b"
ISYNC_ON_SMP
: "=&r" (t)
: "r" (a), "r" (&v->counter)
: "cc", "memory");
return t;
}
static __inline__ void atomic_inc(atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%2 # atomic_inc\n\
addic %0,%0,1\n\
stwcx. %0,0,%2\n\
bne- 1b"
: "=&r" (t), "=m" (v->counter)
: "r" (&v->counter), "m" (v->counter)
: "cc");
}
static __inline__ int atomic_inc_return(atomic_t *v)
{
int t;
__asm__ __volatile__(
EIEIO_ON_SMP
"1: lwarx %0,0,%1 # atomic_inc_return\n\
addic %0,%0,1\n\
stwcx. %0,0,%1\n\
bne- 1b"
ISYNC_ON_SMP
: "=&r" (t)
: "r" (&v->counter)
: "cc", "memory");
return t;
}
/*
* atomic_inc_and_test - increment and test
* @v: pointer of type atomic_t
*
* Atomically increments @v by 1
* and returns true if the result is zero, or false for all
* other cases.
*/
#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
static __inline__ void atomic_dec(atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%2 # atomic_dec\n\
addic %0,%0,-1\n\
stwcx. %0,0,%2\n\
bne- 1b"
: "=&r" (t), "=m" (v->counter)
: "r" (&v->counter), "m" (v->counter)
: "cc");
}
static __inline__ int atomic_dec_return(atomic_t *v)
{
int t;
__asm__ __volatile__(
EIEIO_ON_SMP
"1: lwarx %0,0,%1 # atomic_dec_return\n\
addic %0,%0,-1\n\
stwcx. %0,0,%1\n\
bne- 1b"
ISYNC_ON_SMP
: "=&r" (t)
: "r" (&v->counter)
: "cc", "memory");
return t;
}
#define atomic_sub_and_test(a, v) (atomic_sub_return((a), (v)) == 0)
#define atomic_dec_and_test(v) (atomic_dec_return((v)) == 0)
/*
* Atomically test *v and decrement if it is greater than 0.
* The function returns the old value of *v minus 1.
*/
static __inline__ int atomic_dec_if_positive(atomic_t *v)
{
int t;
__asm__ __volatile__(
EIEIO_ON_SMP
"1: lwarx %0,0,%1 # atomic_dec_if_positive\n\
addic. %0,%0,-1\n\
blt- 2f\n\
stwcx. %0,0,%1\n\
bne- 1b"
ISYNC_ON_SMP
"\n\
2:" : "=&r" (t)
: "r" (&v->counter)
: "cc", "memory");
return t;
}
#define smp_mb__before_atomic_dec() smp_mb()
#define smp_mb__after_atomic_dec() smp_mb()
#define smp_mb__before_atomic_inc() smp_mb()
#define smp_mb__after_atomic_inc() smp_mb()
#endif /* _ASM_PPC64_ATOMIC_H_ */