_outpd -- Write Double Word to Output Port

Format

#include <conio.h>  /* also in <builtin.h> */
unsigned long _outpd( const unsigned int port, const unsigned long value );

Language Level: Extension
_outpd writes an unsigned long value to the specified port. The port number must be a value within the range 0 to 65 535 inclusive. The unsigned long value must be within the range 0 to 4 294 967 295 inclusive.

Note: _outpd is a built-in function, which means it is implemented as an inline instruction and has no backing code in the library. For this reason:

You can run code containing this function only at ring zero. Otherwise, an invalid instruction exception is generated.

Return Value
_outpd returns the unsigned long value that was output to the specified port. There is no error return value, and _outpd does not set errno.

Example
This example uses _outpd to write a doubleword value to a specified output port and return the data written.

#include <builtin.h>
#define LOWER  0
#define UPPER1 65535
#define UPPER2 4294967295
int Add1(int j);
volatile long g;
enum fruit {apples=10, bananas, cantaloupes};
enum fruit f = cantaloupes;
int arr[] = {cantaloupes, bananas, apples};
union
{
   volatile int  i;
   volatile char ch;
} un;
int main(void)
{
   unsigned long l;
   volatile const short c = 0;
   un.i = bananas * f;
   g = _outpd(0,LOWER);
                                     /* ============================= */
                                     /* Types of port number passed : */
                                     /* ----------------------------- */
   l = _outpd(UPPER1, UPPER2);       /* - #define constant            */
   l = _outpd(un.i ,f);              /* - element of union            */
   l = _outpd(Add1(c), apples);      /* - return value from a         */
                                     /*   function call               */
                                     /* ----------------------------- */
   l = _outpd(_outpw(255,Add1(LOWER)),6);
   return 0;
}
int Add1(int j)
{
   j += 1;
   return j;
}



_inp -- Read Byte from Input Port
_inpw -- Read Unsigned Short from Input Port
_inpd -- Read Doubleword from Input Port
_outp -- Write Byte to Output Port
_outpw -- Write Word to Output Port
<builtin.h>
<conio.h>