Linux kernel and analysis How does the second week operating system work?

How does a computer work?

Stored program computer working model, the most basic logical structure of computer system;

The function call stack, the high-level language to run the foundation, only the machine language and the assembly language when the stack mechanism for the computer is not so important, but with the high-level language and functions, the stack becomes the basic function of the computer;

Enter

--PUSHL%EBP

--MOVL%ESP,%EBP

Leave

--MOVL%ebp,%esp

--POPL%EBP

function parameter passing mechanism and local variable storage

Interrupt, multi-channel program operating system base point, no interrupt mechanism program can only run from the beginning to the end of the possibility to start running other programs.

♦ Stack-related registers

–ESP, stacking pointer (stack pointer)

–EBP, Base point pointer (base pointer)

♦ Stack Operations

–push

Stack top address reduced by 4 bytes (32 bits)

–pop

Add 4 bytes to the top address of the stack

♦EBP is used in C to record the current function call base

♦ Other key registers

–CS:EIP: Always point to the next instruction address

• Sequential execution: Always point to the next instruction in consecutive addresses

• Jump/Branch: When executing such an instruction, the value of the CS:EIP is

Modified as required by the program

call: Pushes the value of the current CS:EIP into the top of the stack, Cs:eip points to the

The entry address of the calling function

ret: Eject the value from the top of the stack that was originally saved here, and put the CS:EIP

Into the CS:EIP

The following are the experimental contents:

The Qemu window can see that the my_start_kernel is executing while the My_timer_handler clock interrupt handler is executed periodically.

Kernel header file;

Before executing the MY_START_KERNEL,83 line is hardware initialization, 83 rows and later the operating system.

It's easier to print "My_start_kernel here" 100,000 times per cycle

The same is the initialization of hardware;

Each time the clock interrupt is called once PRINTK, output a ">>>>>>>>my_timer_handler here<<<<<<<<", Interrupt processing action

Wang Xue Cheng

Original works reproduced please indicate the source

"Linux kernel Analysis" MOOC course http://mooc.study.163.com/course/USTC-1000029000

Linux kernel and analysis How does the second week operating system work?