0
INTR
libc%eax = sys_write;int 0x80
0x80
中断或异常
ISR
User mode
intr#
IDT
system_call(){ fn = syscalls[%eax]}
idtr
用户
Mask Points
Kernel mode
内核
IRQs
memory bus
程序
syscallstable
{ printf(\"Hello World\\");}
sys_write(...){ // do real work}
255
CPU
系统调用
PIC
硬件
