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30 行
756 B
30 行
756 B
.text
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.globl switch_to
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switch_to: # switch_to(from, to)
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# save from's registers
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movl 4(%esp), %eax # eax points to from
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popl 0(%eax) # save eip !popl
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movl %esp, 4(%eax)
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movl %ebx, 8(%eax)
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movl %ecx, 12(%eax)
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movl %edx, 16(%eax)
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movl %esi, 20(%eax)
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movl %edi, 24(%eax)
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movl %ebp, 28(%eax)
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# restore to's registers
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movl 4(%esp), %eax # not 8(%esp): popped return address already
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# eax now points to to
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movl 28(%eax), %ebp
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movl 24(%eax), %edi
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movl 20(%eax), %esi
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movl 16(%eax), %edx
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movl 12(%eax), %ecx
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movl 8(%eax), %ebx
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movl 4(%eax), %esp
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pushl 0(%eax) # push eip
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ret
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