asm.s只要实现软、硬中断发生后的响应。代码主要模仿linux的asm.s实现。

asm.s:

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.globl default_handle, timer_interrupt, restore_esp, system_call_interrupt /*全局变量*/

default_handle: /*中断发生后的默认处理*/
?call do_default_handle
?iret

.align 2
timer_interrupt:/*硬件定时器中断*/

/*保留当前所有的寄存器，保留现场*/

?push %ds
?push %es
?push %fs
?push %gs

?pushl %ebp??
?pushl %edi??
?pushl %esi?
?
?pushl %edx??
?pushl %ecx??
?pushl %ebx??
?pushl %eax

?incl jiffies/*刷新jiffies计数器并结束中断*/
?movb $0x020, %al
?outb %al, $0x20

/*esp保存在eax,并将eax值刷新到当前任务current->current_esp*/

?mov %esp, %eax
?call save_esp

/*调用定时器处理函数并做任务调度并将current指向新任务*/
?call do_timer

/*将curret->current_esp的值刷新到esp中*/
?call restore_esp
?mov %eax, %esp
?/*此时已经是新任务的esp了，可以恢复现场并中断返回了。*/
?popl %eax
?popl %ebx
?popl %ecx
?popl %edx

?popl %edi
?popl %esi
?popl %ebp

?pop %gs
?pop %fs
?pop %es
?pop %ds
?
?iret