#define uint  unsigned int
#define uchar unsigned char
typedef union{
              struct
              {
                uchar b0:1;
                uchar b1:1;
                uchar b2:1;
                uchar b3:1;
                uchar b4:1;
                uchar b5:1;
                uchar b6:1;
                uchar b7:1;
        }bit;
        uchar all;
        }reg_8019;
#define reg   *(char *)(0x30000H)        //因为片选是cs0，与本人所用单片机有关
   /************************************************************
             remote dma write
             &transmit packet
             数据包传送方向：单片机M16c-网卡8019-以太网
 ************************************************************/            
void driver send() 
{    
      uchar cr;
      page(0);                             
      cr=*reg                       //commmand register
      
      if(cr==0x26h)                //判断网上是否有数据包发送
                                                       
      queueit();                  //若有，则先排队等待
      else                       //若没有，则远程写
      write_dma(0x4000，COUNT);              //remote dma write
      
      *(reg+5)=count&0xff;               
      *(reg+6)=count>>8;               //local dma-transmit byte count
      *(reg+4)=0x40;                  //tpsr,每次发送数据包都需重新设置此寄存器
      
      *reg=0x26;                       //program NIC to transmit packet
}

void queueit()
{      
        reg_8019 cr;
        page(0);
        cr.all=*reg;                       //command register
        while(cr.bit.b2==1);              //wait until the txp bit equal 0
}

void write_dma(uint address,uint count)   //address为要写入到网卡里的ram的起始地
址
                                          //count为要连续写入的字节数
{       
    uint i;
    reg_8019 isr;
    isr.all=*(reg+7)              //interrupt status register
    uint buffer[768];            //最大数据包1514字节+4字节的校验码
          page(0);
         *(reg+9)=address>>8;          //remote address high
         *(reg+8)=address&0xff;        //remote address low 
         *(reg+11)=count>>8;          //remote  write count high 
        *(reg+10)=count&0xff;        //remote  write count low 
        *reg=0x12 ;                  //remote  dma write and start
        
        i=0;
        while(isr.bit.b6==1)   //wait for the completion of the remote dma write

      {
        *(reg+16)=buffer[i];       //(reg+16）是DMA端口地址(data transfer i/o 
port)

      }
        isr.bit.b6=1;
        *(reg+11)=0;            // count high   中止DMA操作 
        *(reg+10)=0;            // count low
        *reg=0x22;             //abort/complete dma   page 0 

}