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Linux kernel mirror (for testing)
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linux
1#ifndef __ASM_SH_ATOMIC_LLSC_H
2#define __ASM_SH_ATOMIC_LLSC_H
3
4/*
5 * SH-4A note:
6 *
7 * We basically get atomic_xxx_return() for free compared with
8 * atomic_xxx(). movli.l/movco.l require r0 due to the instruction
9 * encoding, so the retval is automatically set without having to
10 * do any special work.
11 */
12/*
13 * To get proper branch prediction for the main line, we must branch
14 * forward to code at the end of this object's .text section, then
15 * branch back to restart the operation.
16 */
17
18#define ATOMIC_OP(op) \
19static inline void atomic_##op(int i, atomic_t *v) \
20{ \
21 unsigned long tmp; \
22 \
23 __asm__ __volatile__ ( \
24"1: movli.l @%2, %0 ! atomic_" #op "\n" \
25" " #op " %1, %0 \n" \
26" movco.l %0, @%2 \n" \
27" bf 1b \n" \
28 : "=&z" (tmp) \
29 : "r" (i), "r" (&v->counter) \
30 : "t"); \
31}
32
33#define ATOMIC_OP_RETURN(op) \
34static inline int atomic_##op##_return(int i, atomic_t *v) \
35{ \
36 unsigned long temp; \
37 \
38 __asm__ __volatile__ ( \
39"1: movli.l @%2, %0 ! atomic_" #op "_return \n" \
40" " #op " %1, %0 \n" \
41" movco.l %0, @%2 \n" \
42" bf 1b \n" \
43" synco \n" \
44 : "=&z" (temp) \
45 : "r" (i), "r" (&v->counter) \
46 : "t"); \
47 \
48 return temp; \
49}
50
51#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op)
52
53ATOMIC_OPS(add)
54ATOMIC_OPS(sub)
55ATOMIC_OP(and)
56ATOMIC_OP(or)
57ATOMIC_OP(xor)
58
59#undef ATOMIC_OPS
60#undef ATOMIC_OP_RETURN
61#undef ATOMIC_OP
62
63#endif /* __ASM_SH_ATOMIC_LLSC_H */