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1 | jermar | 1 | # |
2 | # Copyright (C) 2001-2004 Jakub Jermar |
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3 | # All rights reserved. |
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4 | # |
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5 | # Redistribution and use in source and binary forms, with or without |
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6 | # modification, are permitted provided that the following conditions |
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7 | # are met: |
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8 | # |
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9 | # - Redistributions of source code must retain the above copyright |
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10 | # notice, this list of conditions and the following disclaimer. |
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11 | # - Redistributions in binary form must reproduce the above copyright |
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12 | # notice, this list of conditions and the following disclaimer in the |
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13 | # documentation and/or other materials provided with the distribution. |
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14 | # - The name of the author may not be used to endorse or promote products |
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15 | # derived from this software without specific prior written permission. |
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16 | # |
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17 | # THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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18 | # IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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19 | # OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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20 | # IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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21 | # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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22 | # NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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23 | # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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24 | # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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25 | # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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26 | # THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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27 | # |
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28 | |||
29 | .text |
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30 | |||
31 | .global atomic_inc |
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32 | atomic_inc: |
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33 | pushl %ebx |
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34 | movl 8(%esp),%ebx |
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111 | palkovsky | 35 | #ifdef __SMP__ |
1 | jermar | 36 | lock incl (%ebx) |
111 | palkovsky | 37 | #else |
38 | incl (%ebx) |
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39 | #endif |
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1 | jermar | 40 | popl %ebx |
41 | ret |
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42 | |||
43 | .global atomic_dec |
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44 | atomic_dec: |
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45 | pushl %ebx |
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46 | movl 8(%esp),%ebx |
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111 | palkovsky | 47 | #ifdef __SMP__ |
1 | jermar | 48 | lock decl (%ebx) |
111 | palkovsky | 49 | #else |
50 | decl (%ebx) |
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51 | #endif |
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1 | jermar | 52 | popl %ebx |
53 | ret |
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54 | |||
55 | |||
56 | #ifdef __SMP__ |
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57 | |||
58 | |||
59 | .global test_and_set |
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60 | .global spinlock_arch |
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61 | |||
62 | test_and_set: |
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63 | pushl %ebx |
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64 | |||
65 | movl 8(%esp),%ebx |
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66 | movl $1,%eax |
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67 | xchgl %eax,(%ebx) # xchg implicitly turns on the LOCK signal |
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68 | |||
69 | popl %ebx |
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70 | ret |
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71 | |||
72 | |||
73 | # |
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74 | # This is a bus-and-hyperthreading-friendly implementation of spinlock |
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75 | # |
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76 | spinlock_arch: |
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77 | pushl %eax |
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78 | pushl %ebx |
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79 | |||
80 | movl 12(%esp),%ebx |
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81 | |||
82 | 0: |
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83 | #ifdef __HT__ |
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84 | pause # Pentium 4's with HT love this instruction |
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85 | #endif |
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86 | movl (%ebx),%eax |
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87 | testl %eax,%eax |
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88 | jnz 0b # lightweight looping while it is locked |
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89 | incl %eax |
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90 | xchgl %eax,(%ebx) # now use the atomic operation |
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91 | testl %eax,%eax |
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92 | jnz 0b |
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93 | |||
94 | popl %ebx |
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95 | popl %eax |
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96 | ret |
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97 | |||
98 | #endif |