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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 context_save |
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32 | .global context_restore |
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33 | |||
65 | decky | 34 | |
35 | ## Save current CPU context |
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1 | jermar | 36 | # |
65 | decky | 37 | # Save CPU context to the kernel_context variable |
38 | # pointed by the 1st argument. Returns 1 in EAX. |
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39 | # |
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1 | jermar | 40 | context_save: |
41 | push %ebx |
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42 | |||
43 | movl 4(%esp),%eax # the caller's return %eip |
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44 | movl 8(%esp),%ebx # address of the kernel_context variable to save context to |
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125 | jermar | 45 | movl %eax,4(%ebx) # %eip -> ctx->pc |
1 | jermar | 46 | movl %esp,(%ebx) # %esp -> ctx->sp |
47 | |||
48 | movl %ebx,%eax |
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49 | pop %ebx |
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50 | |||
51 | movl %ebx,8(%eax) |
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52 | movl %ecx,12(%eax) |
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53 | movl %edx,16(%eax) |
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54 | movl %esi,20(%eax) |
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55 | movl %edi,24(%eax) |
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125 | jermar | 56 | movl %ebp,28(%eax) |
57 | |||
1 | jermar | 58 | xorl %eax,%eax # context_save returns 1 |
59 | incl %eax |
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60 | ret |
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65 | decky | 61 | |
62 | |||
63 | ## Restore current CPU context |
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1 | jermar | 64 | # |
65 | decky | 65 | # Restore CPU context from the kernel_context variable |
66 | # pointed by the 1st argument. Returns 0 in EAX. |
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125 | jermar | 67 | # |
1 | jermar | 68 | context_restore: |
69 | movl 4(%esp),%eax # address of the kernel_context variable to restore context from |
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70 | movl (%eax),%esp # ctx->sp -> %esp |
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71 | addl $4,%esp # this is for the pop we don't do |
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72 | |||
73 | movl 8(%eax),%ebx |
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74 | movl 12(%eax),%ecx |
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75 | movl 16(%eax),%edx |
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76 | movl 20(%eax),%esi |
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77 | movl 24(%eax),%edi |
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78 | movl 28(%eax),%ebp |
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79 | |||
80 | movl 4(%eax),%eax |
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81 | movl %eax,(%esp) # ctx->pc -> saver's return %eip |
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125 | jermar | 82 | xorl %eax,%eax # context_restore returns 0 |
1 | jermar | 83 | ret |