/*This C program displays the size of installed extended memory as 
reported by BIOS to CMOS RAM locations 30H and 31H during power-up. */
#include <stdio.h>
#include <dos.h>
main()
{ 
unsigned char b1,b2;
int extmem;
int w;		/* upper byte of word size extended memory */ 	
outp(0x70,0x30);	/* get the low byte */
b1=inp(0x71);
outp(0x70,0x31);	/* get the high byte */
b2=inp(0x71);
w=0x100*b2; /* shift left 2 hex digits to make it upper byte */
extmem=w+b1;	/* add it to lower byte and display the size */
printf("The extended memory installed is: %d KB \n",extmem);
}