Subversion Repositories HelenOS

Rev

Rev 475 | Rev 483 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
1 jermar 1 
/*
112 jermar 2 
 * Copyright (C) 2005 Ondrej Palkovsky
1 jermar 3 
 * All rights reserved.
4 
 *
5 
 * Redistribution and use in source and binary forms, with or without
6 
 * modification, are permitted provided that the following conditions
7 
 * are met:
8 
 *
9 
 * - Redistributions of source code must retain the above copyright
10 
 *   notice, this list of conditions and the following disclaimer.
11 
 * - Redistributions in binary form must reproduce the above copyright
12 
 *   notice, this list of conditions and the following disclaimer in the
13 
 *   documentation and/or other materials provided with the distribution.
14 
 * - The name of the author may not be used to endorse or promote products
15 
 *   derived from this software without specific prior written permission.
16 
 *
17 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 
 */
28 
 
341 jermar 29 
#ifndef __mips32_ATOMIC_H__
30 
#define __mips32_ATOMIC_H__
1 jermar 31 
 
475 jermar 32 
#include <arch/types.h>
33 
 
111 palkovsky 34 
#define atomic_inc(x)   (a_add(x,1))
35 
#define atomic_dec(x)   (a_sub(x,1))
1 jermar 36 
 
477 vana 37 
#define atomic_inc_pre(x) (a_add(x,1)-1)
38 
#define atomic_dec_pre(x) (a_sub(x,1)+1)
39 
 
40 
#define atomic_inc_post(x) (a_add(x,1))
41 
#define atomic_dec_post(x) (a_sub(x,1))
42 
 
43 
 
475 jermar 44 
typedef volatile __u32 atomic_t;
45 
 
111 palkovsky 46 
/*
47 
 * Atomic addition
48 
 *
49 
 * This case is harder, and we have to use the special LL and SC operations
50 
 * to achieve atomicity. The instructions are similar to LW (load) and SW
51 
 * (store), except that the LL (load-linked) instruction loads the address
52 
 * of the variable to a special register and if another process writes to
53 
 * the same location, the SC (store-conditional) instruction fails.
477 vana 54 
 
55 
 Returns (*val)+i
56 
 
111 palkovsky 57 
 */
475 jermar 58 
static inline atomic_t a_add(atomic_t *val, int i)
111 palkovsky 59 
{
475 jermar 60 
    atomic_t tmp, tmp2;
111 palkovsky 61 
 
62 
    asm volatile (
63 
        "   .set    push\n"
64 
        "   .set    noreorder\n"
65 
        "   nop\n"
66 
        "1:\n"
67 
        "   ll  %0, %1\n"
240 palkovsky 68 
        "   addu    %0, %0, %3\n"
69 
        "       move    %2, %0\n"
111 palkovsky 70 
        "   sc  %0, %1\n"
71 
        "   beq %0, 0x0, 1b\n"
240 palkovsky 72 
        "   move    %0, %2\n"
111 palkovsky 73 
        "   .set    pop\n"
240 palkovsky 74 
        : "=&r" (tmp), "=o" (*val), "=r" (tmp2)
75 
        : "r" (i)
111 palkovsky 76 
        );
77 
    return tmp;
78 
}
79 
 
80 
 
81 
/*
82 
 * Atomic subtraction
83 
 *
84 
 * Implemented in the same manner as a_add, except we substract the value.
477 vana 85 
 
86 
 Returns (*val)-i
87 
 
111 palkovsky 88 
 */
475 jermar 89 
static inline atomic_t a_sub(atomic_t *val, int i)
111 palkovsky 90 
 
91 
{
475 jermar 92 
    atomic_t tmp, tmp2;
111 palkovsky 93 
 
94 
    asm volatile (
95 
        "   .set    push\n"
96 
        "   .set    noreorder\n"
97 
        "   nop\n"
98 
        "1:\n"
99 
        "   ll  %0, %1\n"
240 palkovsky 100 
        "   subu    %0, %0, %3\n"
101 
        "       move    %2, %0\n"
111 palkovsky 102 
        "   sc  %0, %1\n"
103 
        "   beq %0, 0x0, 1b\n"
240 palkovsky 104 
        "       move    %0, %2\n"
111 palkovsky 105 
        "   .set    pop\n"
240 palkovsky 106 
        : "=&r" (tmp), "=o" (*val), "=r" (tmp2)
107 
        : "r" (i)
111 palkovsky 108 
        );
109 
    return tmp;
110 
}
111 
 
112 
 
1 jermar 113 
#endif