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add comments on switch.S

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chyyuu 2016-04-11 00:57:53 +08:00
parent f8d953397b
commit 91d8793b24
1 changed files with 14 additions and 14 deletions
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labcodes/lab4/kern/process/switch.S
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@ -5,24 +5,24 @@ switch_to: # switch_to(from, to)
# save from's registers # save from's registers
movl 4(%esp), %eax # eax points to from movl 4(%esp), %eax # eax points to from
popl 0(%eax) # save eip !popl popl 0(%eax) # save eip !popl
movl %esp, 4(%eax) movl %esp, 4(%eax) # save esp::context of from
movl %ebx, 8(%eax) movl %ebx, 8(%eax) # save ebx::context of from
movl %ecx, 12(%eax) movl %ecx, 12(%eax) # save ecx::context of from
movl %edx, 16(%eax) movl %edx, 16(%eax) # save edx::context of from
movl %esi, 20(%eax) movl %esi, 20(%eax) # save esi::context of from
movl %edi, 24(%eax) movl %edi, 24(%eax) # save edi::context of from
movl %ebp, 28(%eax) movl %ebp, 28(%eax) # save ebp::context of from
# restore to's registers # restore to's registers
movl 4(%esp), %eax # not 8(%esp): popped return address already movl 4(%esp), %eax # not 8(%esp): popped return address already
# eax now points to to # eax now points to to
movl 28(%eax), %ebp movl 28(%eax), %ebp # restore ebp::context of to
movl 24(%eax), %edi movl 24(%eax), %edi # restore edi::context of to
movl 20(%eax), %esi movl 20(%eax), %esi # restore esi::context of to
movl 16(%eax), %edx movl 16(%eax), %edx # restore edx::context of to
movl 12(%eax), %ecx movl 12(%eax), %ecx # restore ecx::context of to
movl 8(%eax), %ebx movl 8(%eax), %ebx # restore ebx::context of to
movl 4(%eax), %esp movl 4(%eax), %esp # restore esp::context of to
pushl 0(%eax) # push eip pushl 0(%eax) # push eip