| 1 | #
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| 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 |
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| 29 | .text
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| 30 |
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| 31 | .global context_save
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| 32 | .global context_restore
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| 33 | .global fpu_context_save
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| 34 | .global fpu_context_restore
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| 35 | .global fpu_lazy_context_save
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| 36 | .global fpu_lazy_context_restore
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| 37 |
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| 38 |
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| 39 | ## Save current CPU context
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| 40 | #
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| 41 | # Save CPU context to the kernel_context variable
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| 42 | # pointed by the 1st argument. Returns 1 in EAX.
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| 43 | #
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| 44 | context_save:
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| 45 | push %ebx
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| 46 |
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| 47 | movl 4(%esp),%eax # the caller's return %eip
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| 48 | movl 8(%esp),%ebx # address of the kernel_context variable to save context to
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| 49 | movl %eax,4(%ebx) # %eip -> ctx->pc
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| 50 | movl %esp,(%ebx) # %esp -> ctx->sp
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| 51 |
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| 52 | movl %ebx,%eax
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| 53 | pop %ebx
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| 54 |
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| 55 | movl %ebx,8(%eax)
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| 56 | movl %ecx,12(%eax)
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| 57 | movl %edx,16(%eax)
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| 58 | movl %esi,20(%eax)
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| 59 | movl %edi,24(%eax)
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| 60 | movl %ebp,28(%eax)
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| 61 |
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| 62 | xorl %eax,%eax # context_save returns 1
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| 63 | incl %eax
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| 64 | ret
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| 65 |
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| 66 |
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| 67 | ## Restore current CPU context
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| 68 | #
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| 69 | # Restore CPU context from the kernel_context variable
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| 70 | # pointed by the 1st argument. Returns 0 in EAX.
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| 71 | #
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| 72 | context_restore:
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| 73 | movl 4(%esp),%eax # address of the kernel_context variable to restore context from
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| 74 | movl (%eax),%esp # ctx->sp -> %esp
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| 75 | addl $4,%esp # this is for the pop we don't do
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| 76 |
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| 77 | movl 8(%eax),%ebx
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| 78 | movl 12(%eax),%ecx
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| 79 | movl 16(%eax),%edx
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| 80 | movl 20(%eax),%esi
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| 81 | movl 24(%eax),%edi
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| 82 | movl 28(%eax),%ebp
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| 83 |
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| 84 | movl 4(%eax),%eax
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| 85 | movl %eax,(%esp) # ctx->pc -> saver's return %eip
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| 86 | xorl %eax,%eax # context_restore returns 0
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| 87 | ret
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