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#ifndef _ALPHA_ATOMIC_H
#define _ALPHA_ATOMIC_H
/*
* Atomic operations that C can't guarantee us. Useful for
* resource counting etc...
*
* But use these as seldom as possible since they are much slower
* than regular operations.
*/
#ifdef __SMP__
typedef struct { volatile int counter; } atomic_t;
#else
typedef struct { int counter; } atomic_t;
#endif
#define ATOMIC_INIT(i) ( (atomic_t) { (i) } )
#define atomic_read(v) ((v)->counter)
#define atomic_set(v,i) ((v)->counter = (i))
/*
* Make sure gcc doesn't try to be clever and move things around
* on us. We need to use _exactly_ the address the user gave us,
* not some alias that contains the same information.
*/
#define __atomic_fool_gcc(x) (*(struct { int a[100]; } *)x)
/*
* To get proper branch prediction for the main line, we must branch
* forward to code at the end of this object's .text section, then
* branch back to restart the operation.
*/
extern __inline__ void atomic_add(int i, atomic_t * v)
{
unsigned long temp;
__asm__ __volatile__(
"1: ldl_l %0,%1\n"
" addl %0,%2,%0\n"
" stl_c %0,%1\n"
" beq %0,2f\n"
".section .text2,\"ax\"\n"
"2: br 1b\n"
".previous"
:"=&r" (temp), "=m" (__atomic_fool_gcc(v))
:"Ir" (i), "m" (__atomic_fool_gcc(v)));
}
extern __inline__ void atomic_sub(int i, atomic_t * v)
{
unsigned long temp;
__asm__ __volatile__(
"1: ldl_l %0,%1\n"
" subl %0,%2,%0\n"
" stl_c %0,%1\n"
" beq %0,2f\n"
".section .text2,\"ax\"\n"
"2: br 1b\n"
".previous"
:"=&r" (temp), "=m" (__atomic_fool_gcc(v))
:"Ir" (i), "m" (__atomic_fool_gcc(v)));
}
/*
* Same as above, but return the result value
*/
extern __inline__ long atomic_add_return(int i, atomic_t * v)
{
long temp, result;
__asm__ __volatile__(
"1: ldl_l %0,%1\n"
" addl %0,%3,%0\n"
" mov %0,%2\n"
" stl_c %0,%1\n"
" beq %0,2f\n"
".section .text2,\"ax\"\n"
"2: br 1b\n"
".previous"
:"=&r" (temp), "=m" (__atomic_fool_gcc(v)), "=&r" (result)
:"Ir" (i), "m" (__atomic_fool_gcc(v)));
return result;
}
extern __inline__ long atomic_sub_return(int i, atomic_t * v)
{
long temp, result;
__asm__ __volatile__(
"1: ldl_l %0,%1\n"
" subl %0,%3,%0\n"
" mov %0,%2\n"
" stl_c %0,%1\n"
" beq %0,2f\n"
".section .text2,\"ax\"\n"
"2: br 1b\n"
".previous"
:"=&r" (temp), "=m" (__atomic_fool_gcc(v)), "=&r" (result)
:"Ir" (i), "m" (__atomic_fool_gcc(v)));
return result;
}
#define atomic_dec_return(v) atomic_sub_return(1,(v))
#define atomic_inc_return(v) atomic_add_return(1,(v))
#define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
#define atomic_inc(v) atomic_add(1,(v))
#define atomic_dec(v) atomic_sub(1,(v))
#endif /* _ALPHA_ATOMIC_H */
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