djktime.c

LINUX的简单应用

#include <stdio.h>
#include <stdlib.h>
#include <dos.h>
#include <bios.h>
#include <conio.h>
#include <string.h>

#define COUNTDOWN	 1

#define IntEoiReg			0xFF22		//End-of-Interrupt Register
#define IntMaskReg			0xFF28		//Interrupt Mask Register
#define AMDTimer0CntReg		0xFF50		//AMDTimer0 Count Register
#define AMDTimer2CntReg		0xFF60		//AMDTimer2 Count Register
#define AMDTimer0CmpRegA	0xFF52		//Timer0 Compare Register A
#define AMDTimer2CmpRegA	0xFF62		//Timer2 Compare Register A
#define AMDTimer0Intr		0x0008		//AMDTimer1 Interrupt Number
#define AMDTimer0Eoi		0x0008		//AMDTimer0 EOI

extern void my_int(void);
static void (interrupt far* oldfunc)(void);
static unsigned int delayct;
static unsigned long counter_limit=18;
unsigned int timer=0;

void set_time(int tms)
{
	counter_limit=(unsigned long)(tms/COUNTDOWN);
}

/*static void my_int(void)
{
static int intnum=0;
unsigned char bOut1;
	bOut1=1;
	outportb(BASEIO,bOut1<<(intnum++));
	if(intnum>=8)
		intnum=0;
	printf("1s int\n");
}*/

static void interrupt far time_interrupt()
{
static long counter=0;
//static unsigned int syscounter=0;
    disable();
//	syscounter++;
	counter++;
	delayct++;
    timer++;

	if(counter>=counter_limit)
	{
		counter=0;
		my_int();
		//printf("Syscounter=%f\n",syscounter);
	}

/*	if(syscounter>=128)  //  65536/COUNTDOWN
	{
		syscounter=0;
		oldfunc();
		//printf("counter=%d\n",counter);
	}
	else*/
	outport(IntEoiReg,AMDTimer0Eoi);    //中断结束标志送中断结束寄存器
	enable();
}

void init_timer(int tms)
{
	int mask;
	disable();
	oldfunc = getvect(AMDTimer0Intr);
	set_time(tms);
	mask=inport(IntMaskReg);		//0xff28为中断屏蔽寄存器，取原向量
	mask&=0xfffc;
	outport(IntMaskReg,mask);		//打开定时中断屏蔽位，允许IRQ0；    在定时设置时，以上三句可以不要，因为该位系统初始化就为0 
	outport(AMDTimer0CntReg,0x0);	//ff50为计数器0的当前计数寄存器，因为是加1计数，初始化为0，从0开始计数，否则是个不确定值
	outport(AMDTimer2CntReg,0x0);	//ff60为计数器2的当前计数寄存器，初始化为0
	outport(AMDTimer2CmpRegA,0x2710);	//ff62为计数器2的计数比较寄存器A，用于放计数的最大值，此为十进制10000，
										//计数器2的工作频率为10Mhz(1/4CPU)，此处即为1ms
	outport(AMDTimer0CmpRegA,COUNTDOWN);   //ff52为计数器0的计数比较寄存器A，此为1，1ms，
	setvect(AMDTimer0Intr,time_interrupt);				//设定中断服务程序的入口地址
	enable();
}

void close_timer(void)
{
	disable();
	outport(AMDTimer0CntReg,0x0);	//ff50为计数器0的当前计数寄存器，因为是加1计数，初始化为0，从0开始计数，否则是个不确定值
	outport(AMDTimer2CntReg,0x0);	//ff60为计数器2的当前计数寄存器，初始化为0
	outport(AMDTimer2CmpRegA,1000);	//ff62为计数器2的计数比较寄存器A，用于放计数的最大值
										//计数器2的工作频率为10Mhz(1/4CPU)，此处即为0.1ms
	outport(AMDTimer0CmpRegA,182);   //ff52为计数器0的计数比较寄存器A，此为182，18.2ms，
	setvect(AMDTimer0Intr, oldfunc);
	enable();
}

void my_delay(int tms)
{
unsigned int tlim;
	tlim=(unsigned int)(tms/COUNTDOWN);
	delayct=0;
	while(delayct<tlim)
	{
	}
}