#define SCAN_0 11
#define SHIFT_L 0x0002

#include <bios.h>
#include <stdio.h>

char far *shift_key=0x00400017;

unsigned char Get_Scan_Code(void)
{
asm mov ah,01h
asm int 16h
asm jz empty
asm mov ah,00h
asm int 16h
asm mov al,ah
asm xor ah,ah
asm jmp done
 empty:
asm xor ax,ax
 done:
}

int Test_Scan_Code(int scan)
{
	if(Get_Scan_Code()==scan)
		return(1);
	else
		return(0);
}


unsigned int Get_Control_Keys(unsigned int mask)
{
delay(15);
return(*shift_key&mask);
}

int Test_Combination_Keys(unsigned int mask,int key)
{
   return(Get_Control_Keys(mask)&&Test_Scan_Code(key));
}

void main(void)
{
while(!Test_Combination_Keys(SHIFT_L,SCAN_0));
	printf("SHIFT_L+0");
}