BCD码与十进制的相互转换

BCD码是用每四位代替一位十进制数（0  到 9 的某一位数）  例如：0x25   就代表25    十六进制的每位转换成二进制代表四个位。

下面是bcd转char  short  int  long  c语言程序

//**********************************************************************
// turn byte data to BCD data
//**********************************************************************

unsigned char Byte_BCD(unsigned char Data)

{     if (Data>=99)

       return 0x99;   

        return( Data/10*0x10 + Data%10 ); }

//**********************************************************************

// turn word data to BCD data

//**********************************************************************

void Word_BCD(unsigned char *Ptr, unsigned int Data)

{   

if (Data>=9999)

{       *(Ptr+1) = 0x99;  

     *Ptr = 0x99;     

  return;    }

   *(Ptr+1) = Byte_BCD( (unsigned char)(Data/100) );

   *Ptr = Byte_BCD( (unsigned char)(Data%100) );

}

//**********************************************************************

// turn long data to BCD3 data

//**********************************************************************

void Long_BCD3(unsigned char *Ptr, unsigned long Data)

{  

if (Data>=999999)

{        *(Ptr+2) = 0x99;    

    *(Ptr+1) = 0x99;      

 *Ptr = 0x99;      

 return;     }   

 *(Ptr+2) = Data/100000*0x10 + Data/10000;  

   Word_BCD(Ptr, (unsigned int)(Data%10000));

}

//**********************************************************************

// turn long data to BCD4 data

//**********************************************************************

void Long_BCD4(unsigned char *Ptr, unsigned long Data)

{  

if (Data>=99999999)

{        *(Ptr+3) = 0x99;

       *(Ptr+2) = 0x99;   

     *(Ptr+1) = 0x99;    

    *Ptr = 0x99;      

 return;     }  

Word_BCD(Ptr+2, Data/10000);

 Word_BCD(Ptr, Data%10000);

}

//**********************************************************************

// turn BCD data to byte data

//**********************************************************************

unsigned char BCD_Byte(unsigned char Data)

{   

return(((Data>>4)&0x0f)*10+(Data&0x0f));

}

//**********************************************************************

// turn BCD2 data to word data

//**********************************************************************

unsigned int BCD2_Word(unsigned char *Ptr)

{   

return(  (int)BCD_Byte(*Ptr)+

            (int)BCD_Byte(*(Ptr+1))*100 );

}

//**********************************************************************

// turn BCD3 data to word data

//**********************************************************************

unsigned long BCD3_Long(unsigned char *Ptr)

{

   return(  (long)BCD_Byte(*Ptr)+            

   (long)BCD_Byte(*(Ptr+1))*100+           

  (long)BCD_Byte(*(Ptr+2))*10000 );

}

//**********************************************************************

// turn BCD4 data to word data

//**********************************************************************

unsigned long BCD4_Long(unsigned char *Ptr)

{   

return(  (long)BCD_Byte(*Ptr)+           

  (long)BCD_Byte(*(Ptr+1))*100+          

   (long)BCD_Byte(*(Ptr+2))*10000+            

(long)BCD_Byte(*(Ptr+3))*1000000 );

}