geek OS project 0 （下）
现在我们环境已经搭好了，参考 geekos实验环境的搭建
在main.c中新加个函数，命名为projecto,函数的代码如下：
/*
* GeekOS C code entry point
* Copyright (c) 2001,2003,2004 David H. Hovemeyer <daveho@cs.umd.edu>
* Copyright (c) 2003, Jeffrey K. Hollingsworth <hollings@cs.umd.edu>
* Copyright (c) 2004, Iulian Neamtiu <neamtiu@cs.umd.edu>
* $Revision: 1.51 $
*
* This is free software. You are permitted to use,
* redistribute, and modify it as specified in the file "COPYING".
*/
1#include <geekos/bootinfo.h>
2#include <geekos/string.h>
3#include <geekos/screen.h>
4#include <geekos/mem.h>
5#include <geekos/crc32.h>
6#include <geekos/tss.h>
7#include <geekos/int.h>
8#include <geekos/kthread.h>
9#include <geekos/trap.h>
10#include <geekos/timer.h>
11#include <geekos/keyboard.h>
1//added by 111qqz for project 0
2void project0()
3{
4 Print("To Exit hit Ctrl + d.\n");
5 Print("Hello from 111qqz !\n");
6 Print("This is a test of project0 !\n");
1 Keycode keycode;
2 while(1)
3 {
4 if( Read_Key(&keycode) ) //读取键盘按键状态
5 {
6 if(!( (keycode & KEY_SPECIAL_FLAG) || (keycode & KEY_RELEASE_FLAG)) ) //只处理非特殊按键的按下事件
7 {
8 int asciiCode = keycode & 0xff; //低8位为Ascii码
1 if( (keycode & KEY_CTRL_FLAG)==KEY_CTRL_FLAG && asciiCode=='d') //按下Ctrl键
2 {
3 Print("\n---------BYE!--------\n");
4 Exit(1);
5 }else
6 {
7 Print("%c",(asciiCode=='\r') ? '\n' : asciiCode);
8 }
9 }
10 }
11 }
12}
1/*
2 * Kernel C code entry point.
3 * Initializes kernel subsystems, mounts filesystems,
4 * and spawns init process.
5 */
6void Main(struct Boot_Info* bootInfo)
7{
8 Init_BSS();
9 Init_Screen();
10 Init_Mem(bootInfo);
11 Init_CRC32();
12 Init_TSS();
13 Init_Interrupts();
14 Init_Scheduler();
15 Init_Traps();
16 Init_Timer();
17 Init_Keyboard();
1 Set_Current_Attr(ATTRIB(BLACK, GREEN|BRIGHT));
2 Print("Welcome 111qqz to GeekOS!\n");
3 Set_Current_Attr(ATTRIB(BLACK, GRAY));
1 // TODO("Start a kernel thread to echo pressed keys and print counts");
2 //added by 111qqz for project 0
3 struct Kernel_Thread *thread;
4 thread = Start_Kernel_Thread(&project0,0,PRIORITY_NORMAL,false);
5 // added for project 0 end
1 /* Now this thread is done. */
2 Exit(0);
3}
再修改Main函数，将TODO(“…..这一行替换为以下代码：
struct Kernel_Thread *thread; thread = Start_Kernel_Thread(&project0,0,PRIORITY_NORMAL,false);
替换的意思是，要把TODO那一行注释掉。。。
TODO语句的定义在src/project0/include/geekos/kassert.h中
1#define TODO(message) \
2do { \
3 Set_Current_Attr(ATTRIB(BLUE, GRAY|BRIGHT)); \
4 Print("Unimplemented feature: %s\n", (message)); \
5 while (1) \
6 ; \
7} while (0)
可以看到，这是一个宏打印错误提示后，就直接进入一个死循环中，也就是执行到TODO之后程序就不会继续往下运行了，所以要继续进行调试project0就必须删除或者注释掉那条TODO。
保存代码，按上一篇文章中的方法编译，并在bochs中引导系统。 运行效果如下图所示：
