#include"dos.h"
char key_state[128], key_pressed[128];
/*其中key_state[128]用來表示鍵的當前狀態，key_pressed[128]里保存的值表示哪些鍵被按下，值１表示按下，０表示放開。
*/
void interrupt far  (*OldInt9Handler) ();
/*保存好原來的鍵盤中斷程序地址，以便在程序運行結束后恢復它*/
/*新的鍵盤中斷程序*/
void far interrupt NewInt9 (void)
{
   char ScanCode,temp;

   ScanCode = inportb (0x60);
   temp = inportb (0x61);
   outportb (0x61, temp | 0x80);
   outportb (0x61, temp & 0x7f);
   if (ScanCode & 0x80) {
       ScanCode &= 0x7f;
       key_state[ScanCode] = 0;
   }
   else {
       key_state[ScanCode] = 1;
       key_pressed[ScanCode] = 1;
   }
   outportb (0x20, 0x20);
}
/*安裝新的鍵盤中斷程序的函數*/
void InstallKeyboard (void)
{
   int i;

   for (i = 0; i < 128; i++)
      key_state[i] = key_pressed[i] = 0;
   OldInt9Handler = getvect (9);
   setvect (9, NewInt9);
}
/*恢復舊的鍵盤中斷程序的函數*/
void ShutDownKeyboard (void)
{
   setvect (9, OldInt9Handler);
}
/*讀取按鍵狀態的函數*/
int GetKey (int ScanCode)
{
   int res;

   res = key_state[ScanCode] | key_pressed[ScanCode];
   key_pressed[ScanCode] = 0;
   return res;
}

main ()
{
   int i,press;

   InstallKeyboard ();
   while (GetKey (1)==0){        /*按ESC退出*/
      press = 0;
      for (i = 0; i < 128; i++)
         if (GetKey (i)) {
            press = 1;
            printf ("%4d",i);
         }
      if (press) 
         printf ("\n");
      else
         printf ("\nNokey!\n");
   }
   ShutDownKeyboard ();
}