// gcc -O -o write-cfgreg-with-ioport write-cfgreg-with-ioport.c

#include <stdio.h>
#include <stdlib.h>
#include <sys/io.h>

typedef unsigned long u32;

int main(int argc, char *argv[]){
	int i;
	unsigned int data;

	if(argc < 2){
		printf("USAGE: %s data\n", argv[0]);
		return 1;
	}

	data = strtoul(argv[1], NULL, 16);
	printf("data=%08X\n", data);

	iopl(3);

	u32 bus = 4, dev = 9;
	u32 adr = (bus << 16) | (dev << 11);

	outl(adr|0x80000000, 0xcf8);
	outl(0x00000000 | ((data & 0x3) << 2) , 0xcfc);

	outl(adr|0x80000004, 0xcf8);
	outl(0x00000000 | data & 0xC, 0xcfc);

	outl(adr|0x80000008, 0xcf8);
	outl(0x00000000 | data >> 2 & 0xC, 0xcfc);

	outl(adr|0x8000000C, 0xcf8);
	outl(0x00000000 | data >> 4 & 0xC, 0xcfc);

	outl(0x00000000, 0xcf8);

	iopl(0);

	return 0;
}