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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* $Id: locks.S,v 1.16 2000/02/26 11:02:47 anton Exp $
2 * locks.S: SMP low-level lock primitives on Sparc.
3 *
4 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
5 * Copyright (C) 1998 Anton Blanchard (anton@progsoc.uts.edu.au)
6 * Copyright (C) 1998 Jakub Jelinek (jj@ultra.linux.cz)
7 */
8
9#include <asm/ptrace.h>
10#include <asm/psr.h>
11#include <asm/smp.h>
12#include <asm/spinlock.h>
13
14 .text
15 .align 4
16
17 /* Read/writer locks, as usual this is overly clever to make it
18 * as fast as possible.
19 */
20
21 /* caches... */
22___rw_read_enter_spin_on_wlock:
23 orcc %g2, 0x0, %g0
24 be,a ___rw_read_enter
25 ldstub [%g1 + 3], %g2
26 b ___rw_read_enter_spin_on_wlock
27 ldub [%g1 + 3], %g2
28___rw_read_exit_spin_on_wlock:
29 orcc %g2, 0x0, %g0
30 be,a ___rw_read_exit
31 ldstub [%g1 + 3], %g2
32 b ___rw_read_exit_spin_on_wlock
33 ldub [%g1 + 3], %g2
34___rw_write_enter_spin_on_wlock:
35 orcc %g2, 0x0, %g0
36 be,a ___rw_write_enter
37 ldstub [%g1 + 3], %g2
38 b ___rw_write_enter_spin_on_wlock
39 ld [%g1], %g2
40
41 .globl ___rw_read_enter
42___rw_read_enter:
43 orcc %g2, 0x0, %g0
44 bne,a ___rw_read_enter_spin_on_wlock
45 ldub [%g1 + 3], %g2
46 ld [%g1], %g2
47 add %g2, 1, %g2
48 st %g2, [%g1]
49 retl
50 mov %g4, %o7
51
52 .globl ___rw_read_exit
53___rw_read_exit:
54 orcc %g2, 0x0, %g0
55 bne,a ___rw_read_exit_spin_on_wlock
56 ldub [%g1 + 3], %g2
57 ld [%g1], %g2
58 sub %g2, 0x1ff, %g2
59 st %g2, [%g1]
60 retl
61 mov %g4, %o7
62
63 .globl ___rw_write_enter
64___rw_write_enter:
65 orcc %g2, 0x0, %g0
66 bne ___rw_write_enter_spin_on_wlock
67 ld [%g1], %g2
68 andncc %g2, 0xff, %g0
69 bne,a ___rw_write_enter_spin_on_wlock
70 stb %g0, [%g1 + 3]
71 retl
72 mov %g4, %o7