|
561
|
1
|
|
|
2 /*
|
|
|
3 * Copyright (C) Igor Sysoev
|
|
|
4 */
|
|
|
5
|
|
|
6
|
|
|
7 /*
|
|
|
8 * The ppc assembler treats ";" as comment, so we have to use "\n".
|
|
|
9 * The minus in "bne-" is a hint for the branch prediction unit that
|
|
|
10 * this branch is unlikely to be taken.
|
|
|
11 * The "1b" means the nearest backward label "1" and the "1f" means
|
|
|
12 * the nearest forward label "1".
|
|
|
13 *
|
|
|
14 * The "b" means that the base registers can be used only, i.e.
|
|
|
15 * any register except r0. The r0 register always has a zero value and
|
|
|
16 * could not be used in "addi r0, r0, 1".
|
|
|
17 * The "=&b" means that no input registers can be used.
|
|
|
18 */
|
|
|
19
|
|
|
20 static ngx_inline ngx_atomic_uint_t
|
|
|
21 ngx_atomic_cmp_set(ngx_atomic_t *lock, ngx_atomic_uint_t old,
|
|
|
22 ngx_atomic_uint_t set)
|
|
|
23 {
|
|
|
24 ngx_atomic_uint_t res, temp;
|
|
|
25
|
|
|
26 __asm__ volatile (
|
|
|
27
|
|
|
28 " li %0, 0 \n" /* preset "0" to "res" */
|
|
|
29 " lwarx %1, 0, %2 \n" /* load from [lock] into "temp" */
|
|
|
30 /* and store reservation */
|
|
|
31 " cmpw %1, %3 \n" /* compare "temp" and "old" */
|
|
|
32 " bne- 1f \n" /* not equal */
|
|
|
33 " stwcx. %4, 0, %2 \n" /* store "set" into [lock] if reservation */
|
|
|
34 /* is not cleared */
|
|
|
35 " bne- 1f \n" /* the reservation was cleared */
|
|
|
36 " li %0, 1 \n" /* set "1" to "res" */
|
|
|
37 "1: \n"
|
|
|
38
|
|
|
39 : "=&b" (res), "=&b" (temp)
|
|
|
40 : "b" (lock), "b" (old), "b" (set)
|
|
|
41 : "cc", "memory");
|
|
|
42
|
|
|
43 return res;
|
|
|
44 }
|
|
|
45
|
|
|
46
|
|
|
47 static ngx_inline ngx_atomic_int_t
|
|
|
48 ngx_atomic_fetch_add(ngx_atomic_t *value, ngx_atomic_int_t add)
|
|
|
49 {
|
|
|
50 ngx_atomic_uint_t res, temp;
|
|
|
51
|
|
|
52 __asm__ volatile (
|
|
|
53
|
|
|
54 "1: lwarx %0, 0, %2 \n" /* load from [value] into "res" */
|
|
|
55 /* and store reservation */
|
|
|
56 " add %1, %0, %3 \n" /* "res" + "add" store in "temp" */
|
|
|
57 " stwcx. %1, 0, %2 \n" /* store "temp" into [value] if reservation */
|
|
|
58 /* is not cleared */
|
|
|
59 " bne- 1b \n" /* try again if reservation was cleared */
|
|
|
60
|
|
|
61 : "=&b" (res), "=&b" (temp)
|
|
|
62 : "b" (value), "b" (add)
|
|
|
63 : "cc", "memory");
|
|
|
64
|
|
|
65 return res;
|
|
|
66 }
|
