1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
|
#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.
*/
/*
* Counter is volatile to 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.
*/
typedef struct { volatile int counter; } atomic_t;
#define ATOMIC_INIT(i) ( (atomic_t) { (i) } )
#define atomic_read(v) ((v)->counter)
#define atomic_set(v,i) ((v)->counter = (i))
/*
* 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.
*/
static __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"
".subsection 2\n"
"2: br 1b\n"
".previous"
:"=&r" (temp), "=m" (v->counter)
:"Ir" (i), "m" (v->counter));
}
static __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"
".subsection 2\n"
"2: br 1b\n"
".previous"
:"=&r" (temp), "=m" (v->counter)
:"Ir" (i), "m" (v->counter));
}
/*
* Same as above, but return the result value
*/
static __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"
" mb\n"
".subsection 2\n"
"2: br 1b\n"
".previous"
:"=&r" (temp), "=m" (v->counter), "=&r" (result)
:"Ir" (i), "m" (v->counter) : "memory");
return result;
}
static __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"
" mb\n"
".subsection 2\n"
"2: br 1b\n"
".previous"
:"=&r" (temp), "=m" (v->counter), "=&r" (result)
:"Ir" (i), "m" (v->counter) : "memory");
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 */
|
